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annotate website/src/manual.html.luan @ 387:23d075ce1e48
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| author | Franklin Schmidt <fschmidt@gmail.com> |
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| date | Thu, 23 Apr 2015 18:16:15 -0600 |
| parents | db23f654f87d |
| children | 497d4ef0a89f |
| rev | line source |
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1 local Io = require "luan:Io" |
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2 local Html = require "luan:Html" |
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3 local Http = require "luan:web/Http" |
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4 local Shared = require "site:/Shared" |
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5 |
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6 |
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7 function service() |
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8 Io.stdout = Http.response.text_writer() |
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9 Html.simply_html_page{ |
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10 head = function() %> |
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11 <title>Luan Reference Manual</title> |
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12 <% end; |
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13 body = function() %> |
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14 |
| 372 | 15 <div container> |
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16 <% Shared.header() %> |
| 372 | 17 |
| 18 <h1>Luan Reference Manual</h1> | |
| 19 | |
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20 <p> |
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21 <small> |
| 372 | 22 Original copyright © 2015 Lua.org, PUC-Rio. |
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23 Freely available under the terms of the |
| 372 | 24 <a href="http://www.lua.org/license.html">Lua license</a>. |
| 25 Modified for Luan. | |
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26 </small> |
| 372 | 27 </p> |
| 28 | |
| 29 <hr/> | |
| 30 | |
| 31 <h2>Contents</h2> | |
| 32 | |
| 33 <div margin-bottom="1em"><a href="#intro">Introduction</a></div> | |
| 34 | |
| 373 | 35 <div margin-bottom="1em"> |
| 36 <a href="#basic">Basic Concepts</a> | |
| 37 <ul> | |
| 38 <li><a href="#types">Values and Types</a></li> | |
| 39 <li><a href="#env">Environments</a></li> | |
| 40 <li><a href="#error">Error Handling</a></li> | |
| 41 <li><a href="#meta">Metatables and Metamethods</a></li> | |
| 380 | 42 <li><a href="#gc">Garbage Collection</a></li> |
| 43 </ul> | |
| 44 </div> | |
| 45 | |
| 46 <div margin-bottom="1em"> | |
| 47 <a href="#lang">The Language</a> | |
| 48 <ul> | |
| 49 <li><a href="#lex">Lexical Conventions</a></li> | |
| 50 <li><a href="#vars">Variables</a></li> | |
| 373 | 51 </ul> |
| 52 </div> | |
| 53 | |
| 372 | 54 <hr/> |
| 55 | |
| 373 | 56 |
| 372 | 57 <h2 margin-top="1em"><a name="intro">Introduction</a></h2> |
| 58 | |
| 59 <p>Luan is a high level programming language based on <a href="http://www.lua.org">Lua</a>. A great strength of Lua is its simplicity and Luan takes this even further, being even simpler than Lua. The goal is to provide a simple programming language for the casual programmer with as few concepts as possible so that one can quickly learn the language and then easily understand any code written in Luan.</p> | |
| 60 | |
| 61 <p>Luan is implemented in Java and is tightly coupled with Java. So it makes a great scripting language for Java programmers.</p> | |
| 62 | |
| 63 <p>Unlike Lua which is meant to be embedded, Luan is meant to be a full scripting language. This done not by adding feature to Luan, but rather by providing a complete set of libraries.</p> | |
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64 |
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65 |
| 373 | 66 <h2 margin-top="1em"><a name="basic">Basic Concepts</a></h2> |
| 67 | |
| 68 <p>This section describes the basic concepts of the language.</p> | |
| 69 | |
| 70 <h3 margin-top="1em"><a name="types">Values and Types</a></h3> | |
| 71 | |
| 72 <p> | |
| 73 Luan is a <i>dynamically typed language</i>. | |
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74 This means that |
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75 variables do not have types; only values do. |
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76 There are no type definitions in the language. |
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77 All values carry their own type. |
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78 |
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79 |
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80 <p> |
| 373 | 81 All values in Luan are <i>first-class values</i>. |
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82 This means that all values can be stored in variables, |
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83 passed as arguments to other functions, and returned as results. |
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84 |
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85 |
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86 <p> |
| 373 | 87 There are eight basic types in Luan: |
| 88 <i>nil</i>, <i>boolean</i>, <i>number</i>, | |
| 89 <i>string</i>, <i>binary</i>, <i>function</i>, <i>userdata</i>, | |
| 90 and <i>table</i>. | |
| 91 <i>Nil</i> is the type of the value <b>nil</b>, | |
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92 whose main property is to be different from any other value; |
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93 it usually represents the absence of a useful value. |
| 373 | 94 <i>Nil</i> is implemented as the Java value <i>null</i>. |
| 95 <i>Boolean</i> is the type of the values <b>false</b> and <b>true</b>. | |
| 96 <i>Boolean</i> is implemented as the Java class <i>Boolean</i>. | |
| 97 <i>Number</i> represents both | |
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98 integer numbers and real (floating-point) numbers. |
| 373 | 99 <i>Number</i> is implemented as the Java class <i>Number</i>. Any Java subclass of <i>Number</i> is allowed and this is invisible to the Luan user. Operations on numbers follow the same rules of |
| 100 the underlying Java implementation. | |
| 101 | |
| 102 <i>String</i> is implemented as the Java class <i>String</i>. | |
| 103 <i>Binary</i> is implemented as the Java type <i>byte[]</i>. | |
| 104 | |
| 105 | |
| 106 <p> | |
| 107 Luan can call (and manipulate) functions written in Luan and | |
| 108 functions written in Java (see <a href="#3.4.10">§3.4.10</a>). | |
| 109 Both are represented by the type <i>function</i>. | |
| 110 | |
| 111 | |
| 112 <p> | |
| 113 The type <i>userdata</i> is provided to allow arbitrary Java objects to | |
| 114 be stored in Luan variables. | |
| 115 A userdata value is a Java object that isn't one of the standard Luan types. | |
| 116 Userdata has no predefined operations in Luan, | |
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117 except assignment and identity test. |
| 373 | 118 Userdata is useful then Java access is enabled in Luan |
| 119 | |
| 120 | |
| 121 | |
| 122 <p> | |
| 123 The type <i>table</i> implements associative arrays, | |
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124 that is, arrays that can be indexed not only with numbers, |
| 373 | 125 but with any Luan value except <b>nil</b>. |
| 126 Tables can be <i>heterogeneous</i>; | |
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127 that is, they can contain values of all types (except <b>nil</b>). |
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128 Any key with value <b>nil</b> is not considered part of the table. |
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129 Conversely, any key that is not part of a table has |
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130 an associated value <b>nil</b>. |
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131 |
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132 |
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133 <p> |
| 373 | 134 Tables are the sole data-structuring mechanism in Luan; |
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135 they can be used to represent ordinary arrays, sequences, |
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136 symbol tables, sets, records, graphs, trees, etc. |
| 373 | 137 To represent records, Luan uses the field name as an index. |
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138 The language supports this representation by |
| 373 | 139 providing <tt>a.name</tt> as syntactic sugar for <tt>a["name"]</tt>. |
| 140 There are several convenient ways to create tables in Luan | |
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141 (see <a href="#3.4.9">§3.4.9</a>). |
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142 |
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143 |
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144 <p> |
| 373 | 145 We use the term <i>sequence</i> to denote a table where |
| 146 the set of all positive numeric keys is equal to {1..<i>n</i>} | |
| 147 for some non-negative integer <i>n</i>, | |
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148 which is called the length of the sequence (see <a href="#3.4.7">§3.4.7</a>). |
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149 |
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150 |
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151 <p> |
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152 Like indices, |
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153 the values of table fields can be of any type. |
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154 In particular, |
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155 because functions are first-class values, |
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156 table fields can contain functions. |
| 373 | 157 Thus tables can also carry <i>methods</i> (see <a href="#3.4.11">§3.4.11</a>). |
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158 |
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159 |
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160 <p> |
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161 The indexing of tables follows |
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162 the definition of raw equality in the language. |
| 373 | 163 The expressions <tt>a[i]</tt> and <tt>a[j]</tt> |
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164 denote the same table element |
| 373 | 165 if and only if <tt>i</tt> and <tt>j</tt> are raw equal |
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166 (that is, equal without metamethods). |
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167 In particular, floats with integral values |
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168 are equal to their respective integers |
| 373 | 169 (e.g., <tt>1.0 == 1</tt>). |
| 170 | |
| 171 | |
| 172 <p> | |
| 173 Luan values are <i>objects</i>: | |
| 174 variables do not actually <i>contain</i> values, | |
| 175 only <i>references</i> to them. | |
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176 Assignment, parameter passing, and function returns |
| 373 | 177 always manipulate references to values; |
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178 these operations do not imply any kind of copy. |
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179 |
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180 |
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181 <p> |
| 373 | 182 The library function <a href="#pdf-type"><tt>Luan.type</tt></a> returns a string describing the type |
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183 of a given value (see <a href="#6.1">§6.1</a>). |
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184 |
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185 |
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186 |
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187 |
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188 |
| 373 | 189 <h3 margin-top="1em"><a name="env">Environments</a></h3> |
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190 |
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191 <p> |
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192 As will be discussed in <a href="#3.2">§3.2</a> and <a href="#3.3.3">§3.3.3</a>, |
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193 any reference to a free name |
| 373 | 194 (that is, a name not bound to any declaration) <tt>var</tt> |
| 195 is syntactically translated to <tt>_ENV.var</tt>. | |
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196 Moreover, every chunk is compiled in the scope of |
| 373 | 197 an external local variable named <tt>_ENV</tt> (see <a href="#3.3.2">§3.3.2</a>), |
| 198 so <tt>_ENV</tt> itself is never a free name in a chunk. | |
| 199 | |
| 200 | |
| 201 <p> | |
| 202 Despite the existence of this external <tt>_ENV</tt> variable and | |
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203 the translation of free names, |
| 373 | 204 <tt>_ENV</tt> is a completely regular name. |
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205 In particular, |
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206 you can define new variables and parameters with that name. |
| 373 | 207 Each reference to a free name uses the <tt>_ENV</tt> that is |
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208 visible at that point in the program, |
| 373 | 209 following the usual visibility rules of Luan (see <a href="#3.5">§3.5</a>). |
| 210 | |
| 211 | |
| 212 <p> | |
| 213 Any table used as the value of <tt>_ENV</tt> is called an <i>environment</i>. | |
| 214 | |
| 215 | |
| 216 <p> | |
| 217 When Luan loads a chunk, | |
| 218 the default value for its <tt>_ENV</tt> is an empty table. | |
| 219 | |
| 220 <p> | |
| 221 Luan also provides all chunks with two other local values: <tt>require</tt> and <tt>java</tt>. These are functions used to load and access libraries and other modules. | |
| 222 | |
| 223 | |
| 224 | |
| 225 | |
| 226 <h3 margin-top="1em"><a name="error">Error Handling</a></h3> | |
| 227 | |
| 228 <p> | |
| 229 Luan code can explicitly generate an error by calling the | |
| 230 <a href="#pdf-error"><tt>error</tt></a> function. | |
| 231 If you need to catch errors in Luan, | |
| 232 you can use <a href="#pdf-pcall"><tt>pcall</tt></a> or <a href="#pdf-xpcall"><tt>try</tt></a> | |
| 233 to call a given function in <i>protected mode</i>. | |
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234 |
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235 |
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236 <p> |
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237 Whenever there is an error, |
| 373 | 238 an <i>error object</i> (also called an <i>error message</i>) |
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239 is propagated with information about the error. |
| 373 | 240 Luan itself only generates errors whose error object is a string, |
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241 but programs may generate errors with |
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242 any value as the error object. |
| 373 | 243 It is up to the Luan program or its host to handle such error objects. |
| 244 | |
| 245 | |
| 246 | |
| 247 | |
| 248 | |
| 249 <h3 margin-top="1em"><a name="meta">Metatables and Metamethods</a></h3> | |
| 250 | |
| 251 <p> | |
| 252 Every table in Luan can have a <i>metatable</i>. | |
| 253 This <i>metatable</i> is an ordinary Luan table | |
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254 that defines the behavior of the original value |
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255 under certain special operations. |
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256 You can change several aspects of the behavior |
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257 of operations over a value by setting specific fields in its metatable. |
| 373 | 258 For instance, when a table is the operand of an addition, |
| 259 Luan checks for a function in the field "<tt>__add</tt>" of the table's metatable. | |
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260 If it finds one, |
| 373 | 261 Luan calls this function to perform the addition. |
| 262 | |
| 263 | |
| 264 <p> | |
| 265 The keys in a metatable are derived from the <i>event</i> names; | |
| 266 the corresponding values are called <ii>metamethods</i>. | |
| 267 In the previous example, the event is <tt>"add"</tt> | |
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268 and the metamethod is the function that performs the addition. |
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269 |
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270 |
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271 <p> |
| 373 | 272 You can query the metatable of any table |
| 273 using the <a href="#pdf-getmetatable"><tt>get_metatable</tt></a> function. | |
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274 |
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275 |
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276 <p> |
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277 You can replace the metatable of tables |
| 373 | 278 using the <a href="#pdf-setmetatable"><tt>set_metatable</tt></a> function. |
| 279 | |
| 280 | |
| 281 <p> | |
| 282 A metatable controls how a table behaves in | |
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283 arithmetic operations, bitwise operations, |
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284 order comparisons, concatenation, length operation, calls, and indexing. |
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285 |
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286 |
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287 <p> |
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288 A detailed list of events controlled by metatables is given next. |
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289 Each operation is identified by its corresponding event name. |
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290 The key for each event is a string with its name prefixed by |
| 373 | 291 two underscores, '<tt>__</tt>'; |
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292 for instance, the key for operation "add" is the |
| 373 | 293 string "<tt>__add</tt>". |
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294 Note that queries for metamethods are always raw; |
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295 the access to a metamethod does not invoke other metamethods. |
| 373 | 296 You can emulate how Luan queries a metamethod for an object <tt>obj</tt> |
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297 with the following code: |
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298 |
| 382 | 299 <p><tt><pre> |
| 373 | 300 raw_get(get_metatable(obj) or {}, "__" .. event_name) |
| 382 | 301 </pre></tt></p> |
| 373 | 302 |
| 303 <p> | |
| 304 Here are the events: | |
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305 |
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306 <ul> |
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307 |
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308 <li><b>"add": </b> |
| 373 | 309 the <tt>+</tt> operation. |
| 310 | |
| 311 If any operand for an addition is a table, | |
| 312 Luan will try to call a metamethod. | |
| 313 First, Luan will check the first operand (even if it is valid). | |
| 314 If that operand does not define a metamethod for the "<tt>__add</tt>" event, | |
| 315 then Luan will check the second operand. | |
| 316 If Luan can find a metamethod, | |
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317 it calls the metamethod with the two operands as arguments, |
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318 and the result of the call |
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319 (adjusted to one value) |
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320 is the result of the operation. |
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321 Otherwise, |
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322 it raises an error. |
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323 </li> |
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324 |
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325 <li><b>"sub": </b> |
| 373 | 326 the <tt>-</tt> operation. |
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327 |
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328 Behavior similar to the "add" operation. |
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329 </li> |
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330 |
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331 <li><b>"mul": </b> |
| 373 | 332 the <tt>*</tt> operation. |
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333 |
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334 Behavior similar to the "add" operation. |
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335 </li> |
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336 |
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337 <li><b>"div": </b> |
| 373 | 338 the <tt>/</tt> operation. |
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371
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339 |
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340 Behavior similar to the "add" operation. |
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341 </li> |
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342 |
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343 <li><b>"mod": </b> |
| 373 | 344 the <tt>%</tt> operation. |
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345 |
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346 Behavior similar to the "add" operation. |
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347 </li> |
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348 |
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349 <li><b>"pow": </b> |
| 373 | 350 the <tt>^</tt> (exponentiation) operation. |
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351 |
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352 Behavior similar to the "add" operation. |
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353 </li> |
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354 |
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355 <li><b>"unm": </b> |
| 373 | 356 the <tt>-</tt> (unary minus) operation. |
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357 |
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358 Behavior similar to the "add" operation. |
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359 </li> |
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360 |
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361 <li><b>"concat": </b> |
| 373 | 362 the <tt>..</tt> (concatenation) operation. |
| 363 | |
| 364 Behavior similar to the "add" operation. | |
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371
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365 </li> |
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366 |
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367 <li><b>"len": </b> |
| 373 | 368 the <tt>#</tt> (length) operation. |
| 369 | |
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370 If there is a metamethod, |
| 373 | 371 Luan calls it with the object as argument, |
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372 and the result of the call |
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373 (always adjusted to one value) |
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374 is the result of the operation. |
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375 If there is no metamethod but the object is a table, |
| 373 | 376 then Luan uses the table length operation (see <a href="#3.4.7">§3.4.7</a>). |
| 377 Otherwise, Luan raises an error. | |
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378 </li> |
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379 |
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380 <li><b>"eq": </b> |
| 373 | 381 the <tt>==</tt> (equal) operation. |
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382 |
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383 Behavior similar to the "add" operation, |
| 373 | 384 except that Luan will try a metamethod only when the values |
| 385 being compared are both tables | |
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386 and they are not primitively equal. |
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387 The result of the call is always converted to a boolean. |
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388 </li> |
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389 |
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390 <li><b>"lt": </b> |
| 373 | 391 the <tt><</tt> (less than) operation. |
| 392 | |
| 393 Behavior similar to the "add" operation. | |
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394 The result of the call is always converted to a boolean. |
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395 </li> |
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396 |
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397 <li><b>"le": </b> |
| 373 | 398 the <tt><=</tt> (less equal) operation. |
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371
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399 |
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400 Unlike other operations, |
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401 The less-equal operation can use two different events. |
| 373 | 402 First, Luan looks for the "<tt>__le</tt>" metamethod in both operands, |
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403 like in the "lt" operation. |
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404 If it cannot find such a metamethod, |
| 373 | 405 then it will try the "<tt>__lt</tt>" event, |
| 406 assuming that <tt>a <= b</tt> is equivalent to <tt>not (b < a)</tt>. | |
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407 As with the other comparison operators, |
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408 the result is always a boolean. |
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409 </li> |
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410 |
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411 <li><b>"index": </b> |
| 373 | 412 The indexing access <tt>table[key]</tt>. |
| 413 | |
| 414 This event happens | |
| 415 when <tt>key</tt> is not present in <tt>table</tt>. | |
| 416 The metamethod is looked up in <tt>table</tt>. | |
|
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417 |
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418 |
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419 <p> |
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420 Despite the name, |
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421 the metamethod for this event can be either a function or a table. |
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422 If it is a function, |
| 373 | 423 it is called with <tt>table</tt> and <tt>key</tt> as arguments. |
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424 If it is a table, |
| 373 | 425 the final result is the result of indexing this table with <tt>key</tt>. |
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426 (This indexing is regular, not raw, |
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427 and therefore can trigger another metamethod.) |
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428 </li> |
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429 |
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430 <li><b>"newindex": </b> |
| 373 | 431 The indexing assignment <tt>table[key] = value</tt>. |
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432 |
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433 Like the index event, |
| 373 | 434 this event happens when |
| 435 when <tt>key</tt> is not present in <tt>table</tt>. | |
| 436 The metamethod is looked up in <tt>table</tt>. | |
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437 |
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438 |
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439 <p> |
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440 Like with indexing, |
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441 the metamethod for this event can be either a function or a table. |
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442 If it is a function, |
| 373 | 443 it is called with <tt>table</tt>, <tt>key</tt>, and <tt>value</tt> as arguments. |
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444 If it is a table, |
| 373 | 445 Luan does an indexing assignment to this table with the same key and value. |
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446 (This assignment is regular, not raw, |
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447 and therefore can trigger another metamethod.) |
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448 |
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449 |
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450 <p> |
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451 Whenever there is a "newindex" metamethod, |
| 373 | 452 Luan does not perform the primitive assignment. |
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453 (If necessary, |
| 373 | 454 the metamethod itself can call <a href="#pdf-rawset"><tt>raw_set</tt></a> |
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455 to do the assignment.) |
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456 </li> |
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457 |
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458 <li><b>"call": </b> |
| 373 | 459 The call operation <tt>func(args)</tt>. |
| 460 | |
| 461 This event happens when Luan tries to call a table. | |
| 462 The metamethod is looked up in <tt>func</tt>. | |
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463 If present, |
| 373 | 464 the metamethod is called with <tt>func</tt> as its first argument, |
| 465 followed by the arguments of the original call (<tt>args</tt>). | |
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466 </li> |
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467 |
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468 </ul> |
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469 |
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470 |
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471 |
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472 |
| 380 | 473 <h3 margin-top="1em"><a name="gc">Garbage Collection</a></h3> |
| 474 | |
| 475 <p> | |
| 476 Luan uses Java's garbage collection. | |
| 477 | |
| 478 | |
| 479 | |
| 480 | |
| 481 | |
| 482 <h2 margin-top="1em"><a name="lang">The Language</a></h2> | |
| 483 | |
| 484 <p> | |
| 485 This section describes the lexis, the syntax, and the semantics of Luan. | |
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486 In other words, |
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487 this section describes |
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488 which tokens are valid, |
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489 how they can be combined, |
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490 and what their combinations mean. |
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491 |
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492 |
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493 <p> |
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494 Language constructs will be explained using the usual extended BNF notation, |
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495 in which |
| 380 | 496 {<i>a</i>} means 0 or more <i>a</i>'s, and |
| 497 [<i>a</i>] means an optional <i>a</i>. | |
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498 Non-terminals are shown like non-terminal, |
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499 keywords are shown like <b>kword</b>, |
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500 and other terminal symbols are shown like ‘<b>=</b>’. |
| 380 | 501 The complete syntax of Luan can be found in <a href="#9">§9</a> |
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502 at the end of this manual. |
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503 |
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504 |
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505 |
| 380 | 506 <h3 margin-top="1em"><a name="lex">Lexical Conventions</a></h3> |
| 507 | |
| 508 <p> | |
| 509 Luan ignores spaces and comments | |
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510 between lexical elements (tokens), |
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511 except as delimiters between names and keywords. |
| 380 | 512 Luan generally considers the end of a line to be the end of a statement. This catches errors and encourages readability. The exception to this is in paranthesis ( <i>(...)</i>, <i>[...]</i>, and <i>{...}</i> ) where the end of line is treated as white space. |
| 513 | |
| 514 <p> | |
| 515 <i>Names</i> | |
| 516 (also called <i>identifiers</i>) | |
| 517 in Luan can be any string of letters, | |
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518 digits, and underscores, |
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519 not beginning with a digit. |
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520 Identifiers are used to name variables, table fields, and labels. |
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521 |
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522 |
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523 <p> |
| 380 | 524 The following <i>keywords</i> are reserved |
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525 and cannot be used as names: |
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526 |
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527 |
| 382 | 528 <p><pre> |
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529 and break do else elseif end |
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530 false for function goto if in |
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531 local nil not or repeat return |
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532 then true until while |
| 382 | 533 </pre></p> |
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534 |
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535 <p> |
| 380 | 536 Luan is a case-sensitive language: |
| 537 <tt>and</tt> is a reserved word, but <tt>And</tt> and <tt>AND</tt> | |
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538 are two different, valid names. |
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539 |
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540 |
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541 <p> |
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542 The following strings denote other tokens: |
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543 |
| 382 | 544 <p><pre> |
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545 + - * / % ^ # |
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546 & ~ | << >> // |
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547 == ~= <= >= < > = |
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548 ( ) { } [ ] :: |
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549 ; : , . .. ... |
| 382 | 550 </pre></p> |
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551 |
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552 <p> |
| 380 | 553 <i>Literal strings</i> |
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554 can be delimited by matching single or double quotes, |
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555 and can contain the following C-like escape sequences: |
| 380 | 556 '<tt>\a</tt>' (bell), |
| 557 '<tt>\b</tt>' (backspace), | |
| 558 '<tt>\f</tt>' (form feed), | |
| 559 '<tt>\n</tt>' (newline), | |
| 560 '<tt>\r</tt>' (carriage return), | |
| 561 '<tt>\t</tt>' (horizontal tab), | |
| 562 '<tt>\v</tt>' (vertical tab), | |
| 563 '<tt>\\</tt>' (backslash), | |
| 564 '<tt>\"</tt>' (quotation mark [double quote]), | |
| 565 and '<tt>\'</tt>' (apostrophe [single quote]). | |
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566 A backslash followed by a real newline |
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567 results in a newline in the string. |
| 380 | 568 The escape sequence '<tt>\z</tt>' skips the following span |
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569 of white-space characters, |
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570 including line breaks; |
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571 it is particularly useful to break and indent a long literal string |
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572 into multiple lines without adding the newlines and spaces |
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573 into the string contents. |
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574 |
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575 |
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576 <p> |
| 380 | 577 Luan can specify any character in a literal string by its numerical value. |
|
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578 This can be done |
| 380 | 579 with the escape sequence <tt>\x<i>XX</i></tt>, |
| 580 where <i>XX</i> is a sequence of exactly two hexadecimal digits, | |
| 581 or with the escape sequence <tt>\<i>ddd</i></tt>, | |
| 582 where <i>ddd</i> is a sequence of up to three decimal digits. | |
|
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583 (Note that if a decimal escape sequence is to be followed by a digit, |
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584 it must be expressed using exactly three digits.) |
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585 |
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586 |
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587 <p> |
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588 Literal strings can also be defined using a long format |
| 380 | 589 enclosed by <i>long brackets</i>. |
| 590 We define an <i>opening long bracket of level <i>n</i></i> as an opening | |
| 591 square bracket followed by <i>n</i> equal signs followed by another | |
|
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592 opening square bracket. |
| 380 | 593 So, an opening long bracket of level 0 is written as <tt>[[</tt>, |
| 594 an opening long bracket of level 1 is written as <tt>[=[</tt>, | |
|
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595 and so on. |
| 380 | 596 A <i>closing long bracket</i> is defined similarly; |
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597 for instance, |
| 380 | 598 a closing long bracket of level 4 is written as <tt>]====]</tt>. |
| 599 A <i>long literal</i> starts with an opening long bracket of any level and | |
|
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600 ends at the first closing long bracket of the same level. |
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601 It can contain any text except a closing bracket of the same level. |
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602 Literals in this bracketed form can run for several lines, |
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603 do not interpret any escape sequences, |
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604 and ignore long brackets of any other level. |
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605 Any kind of end-of-line sequence |
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606 (carriage return, newline, carriage return followed by newline, |
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607 or newline followed by carriage return) |
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608 is converted to a simple newline. |
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609 |
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610 |
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611 <p> |
| 380 | 612 Any character in a literal string not |
|
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613 explicitly affected by the previous rules represents itself. |
| 380 | 614 However, Luan opens files for parsing in text mode, |
|
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615 and the system file functions may have problems with |
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616 some control characters. |
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617 So, it is safer to represent |
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618 non-text data as a quoted literal with |
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619 explicit escape sequences for non-text characters. |
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620 |
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621 |
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622 <p> |
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623 For convenience, |
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624 when the opening long bracket is immediately followed by a newline, |
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625 the newline is not included in the string. |
| 380 | 626 As an example |
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627 the five literal strings below denote the same string: |
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628 |
| 382 | 629 <p><pre> |
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630 a = 'alo\n123"' |
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631 a = "alo\n123\"" |
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632 a = '\97lo\10\04923"' |
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633 a = [[alo |
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634 123"]] |
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635 a = [==[ |
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636 alo |
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637 123"]==] |
| 382 | 638 </pre></p> |
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639 |
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640 <p> |
| 380 | 641 A <i>numerical constant</i> (or <i>numeral</i>) |
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642 can be written with an optional fractional part |
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643 and an optional decimal exponent, |
| 380 | 644 marked by a letter '<tt>e</tt>' or '<tt>E</tt>'. |
| 645 Luan also accepts hexadecimal constants, | |
| 646 which start with <tt>0x</tt> or <tt>0X</tt>. | |
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647 Hexadecimal constants also accept an optional fractional part |
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648 plus an optional binary exponent, |
| 380 | 649 marked by a letter '<tt>p</tt>' or '<tt>P</tt>'. |
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650 A numeric constant with a fractional dot or an exponent |
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651 denotes a float; |
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652 otherwise it denotes an integer. |
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653 Examples of valid integer constants are |
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654 |
| 382 | 655 <p><pre> |
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656 3 345 0xff 0xBEBADA |
| 382 | 657 </pre></p> |
| 658 | |
| 659 <p> | |
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660 Examples of valid float constants are |
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661 |
| 382 | 662 <p><pre> |
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663 3.0 3.1416 314.16e-2 0.31416E1 34e1 |
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664 0x0.1E 0xA23p-4 0X1.921FB54442D18P+1 |
| 382 | 665 </pre></p> |
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666 |
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667 <p> |
| 380 | 668 A <i>comment</i> starts with a double hyphen (<tt>--</tt>) |
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669 anywhere outside a string. |
| 380 | 670 If the text immediately after <tt>--</tt> is not an opening long bracket, |
| 671 the comment is a <i>short comment</i>, | |
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672 which runs until the end of the line. |
| 380 | 673 Otherwise, it is a <i>long comment</i>, |
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674 which runs until the corresponding closing long bracket. |
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675 Long comments are frequently used to disable code temporarily. |
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676 |
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677 |
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678 |
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679 |
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680 |
| 380 | 681 <h3 margin-top="1em"><a name="vars">Variables</a></h3> |
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682 |
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683 <p> |
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684 Variables are places that store values. |
| 380 | 685 There are three kinds of variables in Luan: |
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686 global variables, local variables, and table fields. |
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687 |
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688 |
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689 <p> |
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690 A single name can denote a global variable or a local variable |
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691 (or a function's formal parameter, |
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692 which is a particular kind of local variable): |
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693 |
| 382 | 694 <p><pre> |
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695 var ::= Name |
| 382 | 696 </pre></p> |
| 697 | |
| 698 <p> | |
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699 Name denotes identifiers, as defined in <a href="#3.1">§3.1</a>. |
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700 |
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701 |
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702 <p> |
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703 Any variable name is assumed to be global unless explicitly declared |
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704 as a local (see <a href="#3.3.7">§3.3.7</a>). |
| 380 | 705 Local variables are <i>lexically scoped</i>: |
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706 local variables can be freely accessed by functions |
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707 defined inside their scope (see <a href="#3.5">§3.5</a>). |
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708 |
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709 |
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710 <p> |
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711 Before the first assignment to a variable, its value is <b>nil</b>. |
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712 |
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713 |
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714 <p> |
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715 Square brackets are used to index a table: |
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716 |
| 382 | 717 <p><pre> |
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718 var ::= prefixexp ‘<b>[</b>’ exp ‘<b>]</b>’ |
| 382 | 719 </pre></p> |
| 720 | |
| 721 <p> | |
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722 The meaning of accesses to table fields can be changed via metatables. |
| 380 | 723 An access to an indexed variable <tt>t[i]</tt> is equivalent to |
| 724 a call <tt>gettable_event(t,i)</tt>. | |
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725 (See <a href="#2.4">§2.4</a> for a complete description of the |
| 380 | 726 <tt>gettable_event</tt> function. |
| 727 This function is not defined or callable in Luan. | |
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728 We use it here only for explanatory purposes.) |
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729 |
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730 |
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731 <p> |
| 380 | 732 The syntax <tt>var.Name</tt> is just syntactic sugar for |
| 733 <tt>var["Name"]</tt>: | |
|
371
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734 |
| 382 | 735 <p><pre> |
|
371
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736 var ::= prefixexp ‘<b>.</b>’ Name |
| 382 | 737 </pre></p> |
|
371
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738 |
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739 <p> |
| 380 | 740 An access to a global variable <tt>x</tt> |
| 741 is equivalent to <tt>_ENV.x</tt>. | |
|
371
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742 Due to the way that chunks are compiled, |
| 380 | 743 <tt>_ENV</tt> is never a global name (see <a href="#2.2">§2.2</a>). |
|
371
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744 |
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745 |
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746 |
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747 |
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748 |
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749 <h2>3.3 – <a name="3.3">Statements</a></h2> |
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750 |
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751 <p> |
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752 Lua supports an almost conventional set of statements, |
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753 similar to those in Pascal or C. |
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754 This set includes |
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755 assignments, control structures, function calls, |
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756 and variable declarations. |
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757 |
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758 |
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759 |
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760 <h3>3.3.1 – <a name="3.3.1">Blocks</a></h3> |
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761 |
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762 <p> |
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763 A block is a list of statements, |
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764 which are executed sequentially: |
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765 |
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766 <pre> |
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767 block ::= {stat} |
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768 </pre><p> |
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769 Lua has <em>empty statements</em> |
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770 that allow you to separate statements with semicolons, |
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771 start a block with a semicolon |
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772 or write two semicolons in sequence: |
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773 |
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774 <pre> |
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775 stat ::= ‘<b>;</b>’ |
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776 </pre> |
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777 |
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778 <p> |
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779 Function calls and assignments |
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780 can start with an open parenthesis. |
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781 This possibility leads to an ambiguity in Lua's grammar. |
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782 Consider the following fragment: |
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783 |
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784 <pre> |
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785 a = b + c |
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786 (print or io.write)('done') |
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787 </pre><p> |
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788 The grammar could see it in two ways: |
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789 |
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790 <pre> |
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791 a = b + c(print or io.write)('done') |
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792 |
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793 a = b + c; (print or io.write)('done') |
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794 </pre><p> |
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795 The current parser always sees such constructions |
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796 in the first way, |
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797 interpreting the open parenthesis |
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798 as the start of the arguments to a call. |
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799 To avoid this ambiguity, |
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800 it is a good practice to always precede with a semicolon |
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801 statements that start with a parenthesis: |
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802 |
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803 <pre> |
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804 ;(print or io.write)('done') |
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805 </pre> |
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806 |
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807 <p> |
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808 A block can be explicitly delimited to produce a single statement: |
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809 |
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810 <pre> |
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811 stat ::= <b>do</b> block <b>end</b> |
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812 </pre><p> |
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813 Explicit blocks are useful |
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|
814 to control the scope of variable declarations. |
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815 Explicit blocks are also sometimes used to |
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816 add a <b>return</b> statement in the middle |
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817 of another block (see <a href="#3.3.4">§3.3.4</a>). |
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818 |
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819 |
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820 |
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821 |
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822 |
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823 <h3>3.3.2 – <a name="3.3.2">Chunks</a></h3> |
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824 |
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825 <p> |
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826 The unit of compilation of Lua is called a <em>chunk</em>. |
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827 Syntactically, |
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828 a chunk is simply a block: |
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829 |
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830 <pre> |
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831 chunk ::= block |
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832 </pre> |
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833 |
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834 <p> |
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835 Lua handles a chunk as the body of an anonymous function |
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836 with a variable number of arguments |
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837 (see <a href="#3.4.11">§3.4.11</a>). |
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838 As such, chunks can define local variables, |
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839 receive arguments, and return values. |
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840 Moreover, such anonymous function is compiled as in the |
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841 scope of an external local variable called <code>_ENV</code> (see <a href="#2.2">§2.2</a>). |
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842 The resulting function always has <code>_ENV</code> as its only upvalue, |
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843 even if it does not use that variable. |
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844 |
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845 |
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846 <p> |
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847 A chunk can be stored in a file or in a string inside the host program. |
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848 To execute a chunk, |
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849 Lua first <em>loads</em> it, |
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850 precompiling the chunk's code into instructions for a virtual machine, |
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851 and then Lua executes the compiled code |
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852 with an interpreter for the virtual machine. |
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853 |
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854 |
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855 <p> |
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856 Chunks can also be precompiled into binary form; |
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857 see program <code>luac</code> and function <a href="#pdf-string.dump"><code>string.dump</code></a> for details. |
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858 Programs in source and compiled forms are interchangeable; |
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859 Lua automatically detects the file type and acts accordingly (see <a href="#pdf-load"><code>load</code></a>). |
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860 |
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861 |
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862 |
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863 |
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864 |
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865 <h3>3.3.3 – <a name="3.3.3">Assignment</a></h3> |
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866 |
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867 <p> |
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868 Lua allows multiple assignments. |
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869 Therefore, the syntax for assignment |
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870 defines a list of variables on the left side |
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871 and a list of expressions on the right side. |
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872 The elements in both lists are separated by commas: |
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873 |
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874 <pre> |
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875 stat ::= varlist ‘<b>=</b>’ explist |
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876 varlist ::= var {‘<b>,</b>’ var} |
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877 explist ::= exp {‘<b>,</b>’ exp} |
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878 </pre><p> |
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879 Expressions are discussed in <a href="#3.4">§3.4</a>. |
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880 |
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881 |
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882 <p> |
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883 Before the assignment, |
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884 the list of values is <em>adjusted</em> to the length of |
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885 the list of variables. |
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886 If there are more values than needed, |
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887 the excess values are thrown away. |
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888 If there are fewer values than needed, |
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889 the list is extended with as many <b>nil</b>'s as needed. |
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890 If the list of expressions ends with a function call, |
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891 then all values returned by that call enter the list of values, |
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892 before the adjustment |
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893 (except when the call is enclosed in parentheses; see <a href="#3.4">§3.4</a>). |
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894 |
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895 |
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896 <p> |
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897 The assignment statement first evaluates all its expressions |
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898 and only then the assignments are performed. |
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899 Thus the code |
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900 |
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901 <pre> |
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902 i = 3 |
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903 i, a[i] = i+1, 20 |
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904 </pre><p> |
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905 sets <code>a[3]</code> to 20, without affecting <code>a[4]</code> |
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906 because the <code>i</code> in <code>a[i]</code> is evaluated (to 3) |
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907 before it is assigned 4. |
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908 Similarly, the line |
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909 |
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910 <pre> |
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911 x, y = y, x |
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912 </pre><p> |
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913 exchanges the values of <code>x</code> and <code>y</code>, |
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914 and |
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915 |
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916 <pre> |
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917 x, y, z = y, z, x |
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918 </pre><p> |
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919 cyclically permutes the values of <code>x</code>, <code>y</code>, and <code>z</code>. |
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920 |
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921 |
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922 <p> |
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923 The meaning of assignments to global variables |
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924 and table fields can be changed via metatables. |
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925 An assignment to an indexed variable <code>t[i] = val</code> is equivalent to |
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926 <code>settable_event(t,i,val)</code>. |
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927 (See <a href="#2.4">§2.4</a> for a complete description of the |
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928 <code>settable_event</code> function. |
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929 This function is not defined or callable in Lua. |
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930 We use it here only for explanatory purposes.) |
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931 |
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932 |
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933 <p> |
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934 An assignment to a global name <code>x = val</code> |
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935 is equivalent to the assignment |
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936 <code>_ENV.x = val</code> (see <a href="#2.2">§2.2</a>). |
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937 |
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938 |
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939 |
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940 |
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941 |
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942 <h3>3.3.4 – <a name="3.3.4">Control Structures</a></h3><p> |
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943 The control structures |
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944 <b>if</b>, <b>while</b>, and <b>repeat</b> have the usual meaning and |
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945 familiar syntax: |
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946 |
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947 |
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948 |
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949 |
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950 <pre> |
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951 stat ::= <b>while</b> exp <b>do</b> block <b>end</b> |
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952 stat ::= <b>repeat</b> block <b>until</b> exp |
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953 stat ::= <b>if</b> exp <b>then</b> block {<b>elseif</b> exp <b>then</b> block} [<b>else</b> block] <b>end</b> |
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954 </pre><p> |
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955 Lua also has a <b>for</b> statement, in two flavors (see <a href="#3.3.5">§3.3.5</a>). |
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956 |
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957 |
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958 <p> |
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959 The condition expression of a |
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960 control structure can return any value. |
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961 Both <b>false</b> and <b>nil</b> are considered false. |
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962 All values different from <b>nil</b> and <b>false</b> are considered true |
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963 (in particular, the number 0 and the empty string are also true). |
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964 |
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965 |
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966 <p> |
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967 In the <b>repeat</b>–<b>until</b> loop, |
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968 the inner block does not end at the <b>until</b> keyword, |
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969 but only after the condition. |
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970 So, the condition can refer to local variables |
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971 declared inside the loop block. |
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972 |
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973 |
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974 <p> |
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975 The <b>goto</b> statement transfers the program control to a label. |
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976 For syntactical reasons, |
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977 labels in Lua are considered statements too: |
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978 |
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979 |
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980 |
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981 <pre> |
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982 stat ::= <b>goto</b> Name |
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983 stat ::= label |
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984 label ::= ‘<b>::</b>’ Name ‘<b>::</b>’ |
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985 </pre> |
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986 |
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987 <p> |
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988 A label is visible in the entire block where it is defined, |
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989 except |
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990 inside nested blocks where a label with the same name is defined and |
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991 inside nested functions. |
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992 A goto may jump to any visible label as long as it does not |
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993 enter into the scope of a local variable. |
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994 |
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995 |
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996 <p> |
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997 Labels and empty statements are called <em>void statements</em>, |
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998 as they perform no actions. |
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999 |
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1000 |
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1001 <p> |
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1002 The <b>break</b> statement terminates the execution of a |
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1003 <b>while</b>, <b>repeat</b>, or <b>for</b> loop, |
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1004 skipping to the next statement after the loop: |
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1005 |
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1006 |
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1007 <pre> |
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1008 stat ::= <b>break</b> |
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1009 </pre><p> |
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1010 A <b>break</b> ends the innermost enclosing loop. |
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1011 |
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1012 |
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1013 <p> |
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1014 The <b>return</b> statement is used to return values |
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1015 from a function or a chunk |
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1016 (which is an anonymous function). |
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1017 |
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1018 Functions can return more than one value, |
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1019 so the syntax for the <b>return</b> statement is |
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1020 |
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1021 <pre> |
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1022 stat ::= <b>return</b> [explist] [‘<b>;</b>’] |
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1023 </pre> |
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1024 |
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1025 <p> |
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1026 The <b>return</b> statement can only be written |
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1027 as the last statement of a block. |
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1028 If it is really necessary to <b>return</b> in the middle of a block, |
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1029 then an explicit inner block can be used, |
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1030 as in the idiom <code>do return end</code>, |
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1031 because now <b>return</b> is the last statement in its (inner) block. |
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1032 |
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1033 |
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1034 |
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1035 |
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1036 |
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1037 <h3>3.3.5 – <a name="3.3.5">For Statement</a></h3> |
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1038 |
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1039 <p> |
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1040 |
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1041 The <b>for</b> statement has two forms: |
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1042 one numeric and one generic. |
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1043 |
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1044 |
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1045 <p> |
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1046 The numeric <b>for</b> loop repeats a block of code while a |
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1047 control variable runs through an arithmetic progression. |
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1048 It has the following syntax: |
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1049 |
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1050 <pre> |
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1051 stat ::= <b>for</b> Name ‘<b>=</b>’ exp ‘<b>,</b>’ exp [‘<b>,</b>’ exp] <b>do</b> block <b>end</b> |
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1052 </pre><p> |
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1053 The <em>block</em> is repeated for <em>name</em> starting at the value of |
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1054 the first <em>exp</em>, until it passes the second <em>exp</em> by steps of the |
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1055 third <em>exp</em>. |
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1056 More precisely, a <b>for</b> statement like |
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1057 |
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1058 <pre> |
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1059 for v = <em>e1</em>, <em>e2</em>, <em>e3</em> do <em>block</em> end |
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1060 </pre><p> |
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1061 is equivalent to the code: |
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1062 |
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1063 <pre> |
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1064 do |
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1065 local <em>var</em>, <em>limit</em>, <em>step</em> = tonumber(<em>e1</em>), tonumber(<em>e2</em>), tonumber(<em>e3</em>) |
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1066 if not (<em>var</em> and <em>limit</em> and <em>step</em>) then error() end |
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1067 <em>var</em> = <em>var</em> - <em>step</em> |
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1068 while true do |
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1069 <em>var</em> = <em>var</em> + <em>step</em> |
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1070 if (<em>step</em> >= 0 and <em>var</em> > <em>limit</em>) or (<em>step</em> < 0 and <em>var</em> < <em>limit</em>) then |
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1071 break |
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1072 end |
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1073 local v = <em>var</em> |
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1074 <em>block</em> |
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1075 end |
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1076 end |
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1077 </pre> |
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1078 |
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1079 <p> |
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1080 Note the following: |
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1081 |
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1082 <ul> |
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1083 |
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1084 <li> |
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1085 All three control expressions are evaluated only once, |
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1086 before the loop starts. |
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1087 They must all result in numbers. |
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1088 </li> |
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1089 |
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1090 <li> |
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1091 <code><em>var</em></code>, <code><em>limit</em></code>, and <code><em>step</em></code> are invisible variables. |
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1092 The names shown here are for explanatory purposes only. |
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1093 </li> |
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1094 |
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1095 <li> |
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1096 If the third expression (the step) is absent, |
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1097 then a step of 1 is used. |
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1098 </li> |
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1099 |
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1100 <li> |
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1101 You can use <b>break</b> and <b>goto</b> to exit a <b>for</b> loop. |
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1102 </li> |
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1103 |
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1104 <li> |
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1105 The loop variable <code>v</code> is local to the loop body. |
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1106 If you need its value after the loop, |
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1107 assign it to another variable before exiting the loop. |
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1108 </li> |
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1109 |
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1110 </ul> |
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1111 |
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1112 <p> |
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1113 The generic <b>for</b> statement works over functions, |
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1114 called <em>iterators</em>. |
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1115 On each iteration, the iterator function is called to produce a new value, |
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1116 stopping when this new value is <b>nil</b>. |
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1117 The generic <b>for</b> loop has the following syntax: |
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1118 |
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1119 <pre> |
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1120 stat ::= <b>for</b> namelist <b>in</b> explist <b>do</b> block <b>end</b> |
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1121 namelist ::= Name {‘<b>,</b>’ Name} |
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1122 </pre><p> |
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1123 A <b>for</b> statement like |
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1124 |
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1125 <pre> |
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1126 for <em>var_1</em>, ···, <em>var_n</em> in <em>explist</em> do <em>block</em> end |
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1127 </pre><p> |
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1128 is equivalent to the code: |
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1129 |
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1130 <pre> |
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1131 do |
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1132 local <em>f</em>, <em>s</em>, <em>var</em> = <em>explist</em> |
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1133 while true do |
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1134 local <em>var_1</em>, ···, <em>var_n</em> = <em>f</em>(<em>s</em>, <em>var</em>) |
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1135 if <em>var_1</em> == nil then break end |
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1136 <em>var</em> = <em>var_1</em> |
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1137 <em>block</em> |
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1138 end |
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1139 end |
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1140 </pre><p> |
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1141 Note the following: |
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1142 |
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1143 <ul> |
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1144 |
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1145 <li> |
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1146 <code><em>explist</em></code> is evaluated only once. |
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1147 Its results are an <em>iterator</em> function, |
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1148 a <em>state</em>, |
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1149 and an initial value for the first <em>iterator variable</em>. |
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1150 </li> |
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1151 |
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1152 <li> |
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1153 <code><em>f</em></code>, <code><em>s</em></code>, and <code><em>var</em></code> are invisible variables. |
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1154 The names are here for explanatory purposes only. |
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1155 </li> |
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1156 |
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1157 <li> |
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1158 You can use <b>break</b> to exit a <b>for</b> loop. |
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1159 </li> |
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1160 |
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1161 <li> |
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1162 The loop variables <code><em>var_i</em></code> are local to the loop; |
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1163 you cannot use their values after the <b>for</b> ends. |
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1164 If you need these values, |
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1165 then assign them to other variables before breaking or exiting the loop. |
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1166 </li> |
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1167 |
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1168 </ul> |
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1169 |
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1170 |
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1171 |
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1172 |
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1173 <h3>3.3.6 – <a name="3.3.6">Function Calls as Statements</a></h3><p> |
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1174 To allow possible side-effects, |
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1175 function calls can be executed as statements: |
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1176 |
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1177 <pre> |
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1178 stat ::= functioncall |
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1179 </pre><p> |
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1180 In this case, all returned values are thrown away. |
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1181 Function calls are explained in <a href="#3.4.10">§3.4.10</a>. |
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1182 |
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1183 |
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1184 |
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1185 |
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1186 |
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1187 <h3>3.3.7 – <a name="3.3.7">Local Declarations</a></h3><p> |
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1188 Local variables can be declared anywhere inside a block. |
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1189 The declaration can include an initial assignment: |
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1190 |
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1191 <pre> |
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1192 stat ::= <b>local</b> namelist [‘<b>=</b>’ explist] |
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1193 </pre><p> |
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1194 If present, an initial assignment has the same semantics |
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1195 of a multiple assignment (see <a href="#3.3.3">§3.3.3</a>). |
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1196 Otherwise, all variables are initialized with <b>nil</b>. |
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1197 |
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1198 |
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1199 <p> |
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1200 A chunk is also a block (see <a href="#3.3.2">§3.3.2</a>), |
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1201 and so local variables can be declared in a chunk outside any explicit block. |
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1202 |
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1203 |
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1204 <p> |
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1205 The visibility rules for local variables are explained in <a href="#3.5">§3.5</a>. |
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1206 |
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1207 |
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1208 |
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1209 |
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1210 |
|
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1211 |
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1212 |
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1213 <h2>3.4 – <a name="3.4">Expressions</a></h2> |
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1214 |
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1215 <p> |
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1216 The basic expressions in Lua are the following: |
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1217 |
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1218 <pre> |
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1219 exp ::= prefixexp |
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1220 exp ::= <b>nil</b> | <b>false</b> | <b>true</b> |
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1221 exp ::= Numeral |
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1222 exp ::= LiteralString |
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1223 exp ::= functiondef |
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1224 exp ::= tableconstructor |
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1225 exp ::= ‘<b>...</b>’ |
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1226 exp ::= exp binop exp |
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1227 exp ::= unop exp |
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1228 prefixexp ::= var | functioncall | ‘<b>(</b>’ exp ‘<b>)</b>’ |
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1229 </pre> |
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1230 |
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1231 <p> |
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1232 Numerals and literal strings are explained in <a href="#3.1">§3.1</a>; |
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1233 variables are explained in <a href="#3.2">§3.2</a>; |
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1234 function definitions are explained in <a href="#3.4.11">§3.4.11</a>; |
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1235 function calls are explained in <a href="#3.4.10">§3.4.10</a>; |
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1236 table constructors are explained in <a href="#3.4.9">§3.4.9</a>. |
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1237 Vararg expressions, |
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1238 denoted by three dots ('<code>...</code>'), can only be used when |
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1239 directly inside a vararg function; |
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1240 they are explained in <a href="#3.4.11">§3.4.11</a>. |
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1241 |
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1242 |
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1243 <p> |
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1244 Binary operators comprise arithmetic operators (see <a href="#3.4.1">§3.4.1</a>), |
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1245 bitwise operators (see <a href="#3.4.2">§3.4.2</a>), |
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1246 relational operators (see <a href="#3.4.4">§3.4.4</a>), logical operators (see <a href="#3.4.5">§3.4.5</a>), |
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1247 and the concatenation operator (see <a href="#3.4.6">§3.4.6</a>). |
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1248 Unary operators comprise the unary minus (see <a href="#3.4.1">§3.4.1</a>), |
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1249 the unary bitwise not (see <a href="#3.4.2">§3.4.2</a>), |
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1250 the unary logical <b>not</b> (see <a href="#3.4.5">§3.4.5</a>), |
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1251 and the unary <em>length operator</em> (see <a href="#3.4.7">§3.4.7</a>). |
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1252 |
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1253 |
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1254 <p> |
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1255 Both function calls and vararg expressions can result in multiple values. |
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1256 If a function call is used as a statement (see <a href="#3.3.6">§3.3.6</a>), |
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1257 then its return list is adjusted to zero elements, |
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1258 thus discarding all returned values. |
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1259 If an expression is used as the last (or the only) element |
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1260 of a list of expressions, |
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1261 then no adjustment is made |
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1262 (unless the expression is enclosed in parentheses). |
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1263 In all other contexts, |
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1264 Lua adjusts the result list to one element, |
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1265 either discarding all values except the first one |
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1266 or adding a single <b>nil</b> if there are no values. |
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1267 |
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1268 |
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1269 <p> |
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1270 Here are some examples: |
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1271 |
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1272 <pre> |
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1273 f() -- adjusted to 0 results |
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1274 g(f(), x) -- f() is adjusted to 1 result |
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1275 g(x, f()) -- g gets x plus all results from f() |
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1276 a,b,c = f(), x -- f() is adjusted to 1 result (c gets nil) |
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1277 a,b = ... -- a gets the first vararg parameter, b gets |
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1278 -- the second (both a and b can get nil if there |
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1279 -- is no corresponding vararg parameter) |
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1280 |
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1281 a,b,c = x, f() -- f() is adjusted to 2 results |
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1282 a,b,c = f() -- f() is adjusted to 3 results |
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1283 return f() -- returns all results from f() |
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1284 return ... -- returns all received vararg parameters |
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1285 return x,y,f() -- returns x, y, and all results from f() |
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1286 {f()} -- creates a list with all results from f() |
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1287 {...} -- creates a list with all vararg parameters |
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1288 {f(), nil} -- f() is adjusted to 1 result |
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1289 </pre> |
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1290 |
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1291 <p> |
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1292 Any expression enclosed in parentheses always results in only one value. |
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1293 Thus, |
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1294 <code>(f(x,y,z))</code> is always a single value, |
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1295 even if <code>f</code> returns several values. |
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1296 (The value of <code>(f(x,y,z))</code> is the first value returned by <code>f</code> |
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1297 or <b>nil</b> if <code>f</code> does not return any values.) |
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1298 |
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1299 |
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1300 |
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1301 <h3>3.4.1 – <a name="3.4.1">Arithmetic Operators</a></h3><p> |
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1302 Lua supports the following arithmetic operators: |
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1303 |
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1304 <ul> |
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1305 <li><b><code>+</code>: </b>addition</li> |
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1306 <li><b><code>-</code>: </b>subtraction</li> |
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1307 <li><b><code>*</code>: </b>multiplication</li> |
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1308 <li><b><code>/</code>: </b>float division</li> |
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1309 <li><b><code>//</code>: </b>floor division</li> |
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1310 <li><b><code>%</code>: </b>modulo</li> |
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1311 <li><b><code>^</code>: </b>exponentiation</li> |
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1312 <li><b><code>-</code>: </b>unary minus</li> |
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1313 </ul> |
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1314 |
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1315 <p> |
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1316 With the exception of exponentiation and float division, |
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1317 the arithmetic operators work as follows: |
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1318 If both operands are integers, |
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1319 the operation is performed over integers and the result is an integer. |
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1320 Otherwise, if both operands are numbers |
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1321 or strings that can be converted to |
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1322 numbers (see <a href="#3.4.3">§3.4.3</a>), |
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1323 then they are converted to floats, |
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1324 the operation is performed following the usual rules |
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1325 for floating-point arithmetic |
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1326 (usually the IEEE 754 standard), |
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1327 and the result is a float. |
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1328 |
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1329 |
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1330 <p> |
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1331 Exponentiation and float division (<code>/</code>) |
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1332 always convert their operands to floats |
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1333 and the result is always a float. |
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1334 Exponentiation uses the ISO C function <code>pow</code>, |
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1335 so that it works for non-integer exponents too. |
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1336 |
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1337 |
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1338 <p> |
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1339 Floor division (<code>//</code>) is a division |
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1340 that rounds the quotient towards minus infinite, |
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1341 that is, the floor of the division of its operands. |
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1342 |
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1343 |
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1344 <p> |
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1345 Modulo is defined as the remainder of a division |
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1346 that rounds the quotient towards minus infinite (floor division). |
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1347 |
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1348 |
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1349 <p> |
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1350 In case of overflows in integer arithmetic, |
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1351 all operations <em>wrap around</em>, |
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1352 according to the usual rules of two-complement arithmetic. |
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1353 (In other words, |
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1354 they return the unique representable integer |
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1355 that is equal modulo <em>2<sup>64</sup></em> to the mathematical result.) |
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1356 |
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1357 |
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1358 |
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1359 <h3>3.4.2 – <a name="3.4.2">Bitwise Operators</a></h3><p> |
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1360 Lua supports the following bitwise operators: |
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1361 |
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1362 <ul> |
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1363 <li><b><code>&</code>: </b>bitwise and</li> |
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1364 <li><b><code>|</code>: </b>bitwise or</li> |
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1365 <li><b><code>~</code>: </b>bitwise exclusive or</li> |
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1366 <li><b><code>>></code>: </b>right shift</li> |
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1367 <li><b><code><<</code>: </b>left shift</li> |
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1368 <li><b><code>~</code>: </b>unary bitwise not</li> |
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1369 </ul> |
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1370 |
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1371 <p> |
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1372 All bitwise operations convert its operands to integers |
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1373 (see <a href="#3.4.3">§3.4.3</a>), |
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1374 operate on all bits of those integers, |
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1375 and result in an integer. |
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1376 |
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1377 |
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1378 <p> |
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1379 Both right and left shifts fill the vacant bits with zeros. |
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1380 Negative displacements shift to the other direction; |
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1381 displacements with absolute values equal to or higher than |
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1382 the number of bits in an integer |
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1383 result in zero (as all bits are shifted out). |
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1384 |
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1385 |
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1386 |
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1387 |
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1388 |
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1389 <h3>3.4.3 – <a name="3.4.3">Coercions and Conversions</a></h3><p> |
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1390 Lua provides some automatic conversions between some |
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1391 types and representations at run time. |
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1392 Bitwise operators always convert float operands to integers. |
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1393 Exponentiation and float division |
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1394 always convert integer operands to floats. |
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1395 All other arithmetic operations applied to mixed numbers |
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1396 (integers and floats) convert the integer operand to a float; |
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1397 this is called the <em>usual rule</em>. |
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1398 The C API also converts both integers to floats and |
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1399 floats to integers, as needed. |
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1400 Moreover, string concatenation accepts numbers as arguments, |
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1401 besides strings. |
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1402 |
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1403 |
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1404 <p> |
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1405 Lua also converts strings to numbers, |
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1406 whenever a number is expected. |
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1407 |
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1408 |
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1409 <p> |
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1410 In a conversion from integer to float, |
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1411 if the integer value has an exact representation as a float, |
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1412 that is the result. |
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1413 Otherwise, |
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1414 the conversion gets the nearest higher or |
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1415 the nearest lower representable value. |
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1416 This kind of conversion never fails. |
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1417 |
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1418 |
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1419 <p> |
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1420 The conversion from float to integer |
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1421 checks whether the float has an exact representation as an integer |
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1422 (that is, the float has an integral value and |
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1423 it is in the range of integer representation). |
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1424 If it does, that representation is the result. |
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1425 Otherwise, the conversion fails. |
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1426 |
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1427 |
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1428 <p> |
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1429 The conversion from strings to numbers goes as follows: |
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1430 First, the string is converted to an integer or a float, |
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1431 following its syntax and the rules of the Lua lexer. |
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1432 (The string may have also leading and trailing spaces and a sign.) |
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1433 Then, the resulting number is converted to the required type |
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1434 (float or integer) according to the previous rules. |
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1435 |
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1436 |
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1437 <p> |
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1438 The conversion from numbers to strings uses a |
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1439 non-specified human-readable format. |
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1440 For complete control over how numbers are converted to strings, |
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1441 use the <code>format</code> function from the string library |
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1442 (see <a href="#pdf-string.format"><code>string.format</code></a>). |
|
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1443 |
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1444 |
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1445 |
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1446 |
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1447 |
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1448 <h3>3.4.4 – <a name="3.4.4">Relational Operators</a></h3><p> |
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1449 Lua supports the following relational operators: |
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1450 |
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1451 <ul> |
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1452 <li><b><code>==</code>: </b>equality</li> |
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1453 <li><b><code>~=</code>: </b>inequality</li> |
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1454 <li><b><code><</code>: </b>less than</li> |
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1455 <li><b><code>></code>: </b>greater than</li> |
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1456 <li><b><code><=</code>: </b>less or equal</li> |
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1457 <li><b><code>>=</code>: </b>greater or equal</li> |
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1458 </ul><p> |
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1459 These operators always result in <b>false</b> or <b>true</b>. |
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1460 |
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1461 |
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1462 <p> |
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1463 Equality (<code>==</code>) first compares the type of its operands. |
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1464 If the types are different, then the result is <b>false</b>. |
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1465 Otherwise, the values of the operands are compared. |
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1466 Strings are compared in the obvious way. |
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1467 Numbers follow the usual rule for binary operations: |
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1468 if both operands are integers, |
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1469 they are compared as integers; |
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1470 otherwise, they are converted to floats |
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1471 and compared as such. |
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1472 |
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1473 |
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1474 <p> |
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1475 Tables, userdata, and threads |
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1476 are compared by reference: |
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1477 two objects are considered equal only if they are the same object. |
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1478 Every time you create a new object |
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1479 (a table, userdata, or thread), |
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1480 this new object is different from any previously existing object. |
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1481 Closures with the same reference are always equal. |
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1482 Closures with any detectable difference |
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1483 (different behavior, different definition) are always different. |
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1484 |
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1485 |
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1486 <p> |
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1487 You can change the way that Lua compares tables and userdata |
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1488 by using the "eq" metamethod (see <a href="#2.4">§2.4</a>). |
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1489 |
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1490 |
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1491 <p> |
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1492 Equality comparisons do not convert strings to numbers |
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1493 or vice versa. |
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1494 Thus, <code>"0"==0</code> evaluates to <b>false</b>, |
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1495 and <code>t[0]</code> and <code>t["0"]</code> denote different |
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1496 entries in a table. |
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1497 |
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1498 |
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1499 <p> |
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1500 The operator <code>~=</code> is exactly the negation of equality (<code>==</code>). |
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1501 |
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1502 |
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1503 <p> |
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1504 The order operators work as follows. |
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1505 If both arguments are numbers, |
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1506 then they are compared following |
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1507 the usual rule for binary operations. |
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1508 Otherwise, if both arguments are strings, |
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1509 then their values are compared according to the current locale. |
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1510 Otherwise, Lua tries to call the "lt" or the "le" |
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1511 metamethod (see <a href="#2.4">§2.4</a>). |
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1512 A comparison <code>a > b</code> is translated to <code>b < a</code> |
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1513 and <code>a >= b</code> is translated to <code>b <= a</code>. |
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1514 |
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1515 |
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1516 |
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1517 |
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1518 |
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1519 <h3>3.4.5 – <a name="3.4.5">Logical Operators</a></h3><p> |
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1520 The logical operators in Lua are |
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1521 <b>and</b>, <b>or</b>, and <b>not</b>. |
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1522 Like the control structures (see <a href="#3.3.4">§3.3.4</a>), |
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1523 all logical operators consider both <b>false</b> and <b>nil</b> as false |
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1524 and anything else as true. |
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1525 |
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1526 |
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1527 <p> |
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1528 The negation operator <b>not</b> always returns <b>false</b> or <b>true</b>. |
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1529 The conjunction operator <b>and</b> returns its first argument |
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1530 if this value is <b>false</b> or <b>nil</b>; |
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1531 otherwise, <b>and</b> returns its second argument. |
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1532 The disjunction operator <b>or</b> returns its first argument |
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1533 if this value is different from <b>nil</b> and <b>false</b>; |
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1534 otherwise, <b>or</b> returns its second argument. |
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1535 Both <b>and</b> and <b>or</b> use short-circuit evaluation; |
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1536 that is, |
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1537 the second operand is evaluated only if necessary. |
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1538 Here are some examples: |
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1539 |
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1540 <pre> |
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1541 10 or 20 --> 10 |
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1542 10 or error() --> 10 |
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1543 nil or "a" --> "a" |
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1544 nil and 10 --> nil |
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1545 false and error() --> false |
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1546 false and nil --> false |
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1547 false or nil --> nil |
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1548 10 and 20 --> 20 |
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1549 </pre><p> |
|
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1550 (In this manual, |
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1551 <code>--></code> indicates the result of the preceding expression.) |
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1552 |
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1553 |
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1554 |
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1555 |
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1556 |
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1557 <h3>3.4.6 – <a name="3.4.6">Concatenation</a></h3><p> |
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1558 The string concatenation operator in Lua is |
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|
1559 denoted by two dots ('<code>..</code>'). |
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1560 If both operands are strings or numbers, then they are converted to |
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1561 strings according to the rules described in <a href="#3.4.3">§3.4.3</a>. |
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1562 Otherwise, the <code>__concat</code> metamethod is called (see <a href="#2.4">§2.4</a>). |
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1563 |
|
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1564 |
|
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1565 |
|
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1566 |
|
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1567 |
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1568 <h3>3.4.7 – <a name="3.4.7">The Length Operator</a></h3> |
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1569 |
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1570 <p> |
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1571 The length operator is denoted by the unary prefix operator <code>#</code>. |
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1572 The length of a string is its number of bytes |
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1573 (that is, the usual meaning of string length when each |
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1574 character is one byte). |
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1575 |
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1576 |
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1577 <p> |
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1578 A program can modify the behavior of the length operator for |
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1579 any value but strings through the <code>__len</code> metamethod (see <a href="#2.4">§2.4</a>). |
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1580 |
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1581 |
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1582 <p> |
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1583 Unless a <code>__len</code> metamethod is given, |
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1584 the length of a table <code>t</code> is only defined if the |
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1585 table is a <em>sequence</em>, |
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1586 that is, |
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1587 the set of its positive numeric keys is equal to <em>{1..n}</em> |
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1588 for some non-negative integer <em>n</em>. |
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1589 In that case, <em>n</em> is its length. |
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1590 Note that a table like |
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1591 |
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1592 <pre> |
|
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1593 {10, 20, nil, 40} |
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1594 </pre><p> |
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1595 is not a sequence, because it has the key <code>4</code> |
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1596 but does not have the key <code>3</code>. |
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1597 (So, there is no <em>n</em> such that the set <em>{1..n}</em> is equal |
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1598 to the set of positive numeric keys of that table.) |
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1599 Note, however, that non-numeric keys do not interfere |
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1600 with whether a table is a sequence. |
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1601 |
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1602 |
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1603 |
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1604 |
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1605 |
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1606 <h3>3.4.8 – <a name="3.4.8">Precedence</a></h3><p> |
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1607 Operator precedence in Lua follows the table below, |
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1608 from lower to higher priority: |
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1609 |
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1610 <pre> |
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1611 or |
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1612 and |
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1613 < > <= >= ~= == |
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1614 | |
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1615 ~ |
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1616 & |
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1617 << >> |
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1618 .. |
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1619 + - |
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1620 * / // % |
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1621 unary operators (not # - ~) |
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1622 ^ |
|
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1623 </pre><p> |
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1624 As usual, |
|
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1625 you can use parentheses to change the precedences of an expression. |
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1626 The concatenation ('<code>..</code>') and exponentiation ('<code>^</code>') |
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1627 operators are right associative. |
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1628 All other binary operators are left associative. |
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1629 |
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1630 |
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1631 |
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1632 |
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1633 |
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1634 <h3>3.4.9 – <a name="3.4.9">Table Constructors</a></h3><p> |
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1635 Table constructors are expressions that create tables. |
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1636 Every time a constructor is evaluated, a new table is created. |
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1637 A constructor can be used to create an empty table |
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1638 or to create a table and initialize some of its fields. |
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1639 The general syntax for constructors is |
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1640 |
|
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1641 <pre> |
|
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1642 tableconstructor ::= ‘<b>{</b>’ [fieldlist] ‘<b>}</b>’ |
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1643 fieldlist ::= field {fieldsep field} [fieldsep] |
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1644 field ::= ‘<b>[</b>’ exp ‘<b>]</b>’ ‘<b>=</b>’ exp | Name ‘<b>=</b>’ exp | exp |
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1645 fieldsep ::= ‘<b>,</b>’ | ‘<b>;</b>’ |
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1646 </pre> |
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1647 |
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1648 <p> |
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1649 Each field of the form <code>[exp1] = exp2</code> adds to the new table an entry |
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1650 with key <code>exp1</code> and value <code>exp2</code>. |
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1651 A field of the form <code>name = exp</code> is equivalent to |
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1652 <code>["name"] = exp</code>. |
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1653 Finally, fields of the form <code>exp</code> are equivalent to |
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1654 <code>[i] = exp</code>, where <code>i</code> are consecutive integers |
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1655 starting with 1. |
|
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1656 Fields in the other formats do not affect this counting. |
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1657 For example, |
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1658 |
|
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1659 <pre> |
|
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1660 a = { [f(1)] = g; "x", "y"; x = 1, f(x), [30] = 23; 45 } |
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1661 </pre><p> |
|
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1662 is equivalent to |
|
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|
1663 |
|
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1664 <pre> |
|
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1665 do |
|
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1666 local t = {} |
|
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1667 t[f(1)] = g |
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1668 t[1] = "x" -- 1st exp |
|
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1669 t[2] = "y" -- 2nd exp |
|
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1670 t.x = 1 -- t["x"] = 1 |
|
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1671 t[3] = f(x) -- 3rd exp |
|
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1672 t[30] = 23 |
|
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1673 t[4] = 45 -- 4th exp |
|
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1674 a = t |
|
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1675 end |
|
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|
1676 </pre> |
|
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1677 |
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1678 <p> |
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1679 The order of the assignments in a constructor is undefined. |
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1680 (This order would be relevant only when there are repeated keys.) |
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1681 |
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1682 |
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1683 <p> |
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1684 If the last field in the list has the form <code>exp</code> |
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1685 and the expression is a function call or a vararg expression, |
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1686 then all values returned by this expression enter the list consecutively |
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1687 (see <a href="#3.4.10">§3.4.10</a>). |
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1688 |
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1689 |
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1690 <p> |
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1691 The field list can have an optional trailing separator, |
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1692 as a convenience for machine-generated code. |
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1693 |
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1694 |
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1695 |
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1696 |
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1697 |
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1698 <h3>3.4.10 – <a name="3.4.10">Function Calls</a></h3><p> |
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1699 A function call in Lua has the following syntax: |
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1700 |
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1701 <pre> |
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1702 functioncall ::= prefixexp args |
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1703 </pre><p> |
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1704 In a function call, |
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1705 first prefixexp and args are evaluated. |
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1706 If the value of prefixexp has type <em>function</em>, |
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1707 then this function is called |
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1708 with the given arguments. |
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1709 Otherwise, the prefixexp "call" metamethod is called, |
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1710 having as first parameter the value of prefixexp, |
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1711 followed by the original call arguments |
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1712 (see <a href="#2.4">§2.4</a>). |
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1713 |
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1714 |
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1715 <p> |
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1716 The form |
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1717 |
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1718 <pre> |
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1719 functioncall ::= prefixexp ‘<b>:</b>’ Name args |
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1720 </pre><p> |
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1721 can be used to call "methods". |
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1722 A call <code>v:name(<em>args</em>)</code> |
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1723 is syntactic sugar for <code>v.name(v,<em>args</em>)</code>, |
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1724 except that <code>v</code> is evaluated only once. |
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1725 |
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1726 |
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1727 <p> |
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1728 Arguments have the following syntax: |
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1729 |
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1730 <pre> |
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1731 args ::= ‘<b>(</b>’ [explist] ‘<b>)</b>’ |
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1732 args ::= tableconstructor |
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1733 args ::= LiteralString |
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1734 </pre><p> |
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1735 All argument expressions are evaluated before the call. |
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1736 A call of the form <code>f{<em>fields</em>}</code> is |
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1737 syntactic sugar for <code>f({<em>fields</em>})</code>; |
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1738 that is, the argument list is a single new table. |
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1739 A call of the form <code>f'<em>string</em>'</code> |
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1740 (or <code>f"<em>string</em>"</code> or <code>f[[<em>string</em>]]</code>) |
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1741 is syntactic sugar for <code>f('<em>string</em>')</code>; |
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1742 that is, the argument list is a single literal string. |
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1743 |
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1744 |
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1745 <p> |
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1746 A call of the form <code>return <em>functioncall</em></code> is called |
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1747 a <em>tail call</em>. |
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1748 Lua implements <em>proper tail calls</em> |
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1749 (or <em>proper tail recursion</em>): |
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1750 in a tail call, |
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1751 the called function reuses the stack entry of the calling function. |
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1752 Therefore, there is no limit on the number of nested tail calls that |
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1753 a program can execute. |
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1754 However, a tail call erases any debug information about the |
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1755 calling function. |
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1756 Note that a tail call only happens with a particular syntax, |
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1757 where the <b>return</b> has one single function call as argument; |
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1758 this syntax makes the calling function return exactly |
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1759 the returns of the called function. |
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1760 So, none of the following examples are tail calls: |
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1761 |
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1762 <pre> |
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1763 return (f(x)) -- results adjusted to 1 |
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1764 return 2 * f(x) |
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1765 return x, f(x) -- additional results |
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1766 f(x); return -- results discarded |
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1767 return x or f(x) -- results adjusted to 1 |
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1768 </pre> |
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1769 |
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1770 |
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1771 |
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1772 |
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1773 <h3>3.4.11 – <a name="3.4.11">Function Definitions</a></h3> |
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1774 |
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1775 <p> |
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1776 The syntax for function definition is |
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1777 |
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1778 <pre> |
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1779 functiondef ::= <b>function</b> funcbody |
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1780 funcbody ::= ‘<b>(</b>’ [parlist] ‘<b>)</b>’ block <b>end</b> |
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1781 </pre> |
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1782 |
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1783 <p> |
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1784 The following syntactic sugar simplifies function definitions: |
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1785 |
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1786 <pre> |
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1787 stat ::= <b>function</b> funcname funcbody |
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1788 stat ::= <b>local</b> <b>function</b> Name funcbody |
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1789 funcname ::= Name {‘<b>.</b>’ Name} [‘<b>:</b>’ Name] |
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1790 </pre><p> |
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1791 The statement |
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1792 |
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1793 <pre> |
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1794 function f () <em>body</em> end |
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1795 </pre><p> |
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1796 translates to |
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1797 |
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1798 <pre> |
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1799 f = function () <em>body</em> end |
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1800 </pre><p> |
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1801 The statement |
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1802 |
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1803 <pre> |
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1804 function t.a.b.c.f () <em>body</em> end |
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1805 </pre><p> |
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1806 translates to |
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1807 |
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1808 <pre> |
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1809 t.a.b.c.f = function () <em>body</em> end |
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1810 </pre><p> |
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1811 The statement |
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1812 |
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1813 <pre> |
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1814 local function f () <em>body</em> end |
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1815 </pre><p> |
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1816 translates to |
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1817 |
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1818 <pre> |
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1819 local f; f = function () <em>body</em> end |
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1820 </pre><p> |
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1821 not to |
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1822 |
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1823 <pre> |
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1824 local f = function () <em>body</em> end |
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1825 </pre><p> |
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1826 (This only makes a difference when the body of the function |
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1827 contains references to <code>f</code>.) |
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1828 |
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1829 |
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1830 <p> |
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1831 A function definition is an executable expression, |
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1832 whose value has type <em>function</em>. |
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1833 When Lua precompiles a chunk, |
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1834 all its function bodies are precompiled too. |
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1835 Then, whenever Lua executes the function definition, |
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1836 the function is <em>instantiated</em> (or <em>closed</em>). |
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1837 This function instance (or <em>closure</em>) |
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1838 is the final value of the expression. |
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1839 |
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1840 |
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1841 <p> |
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1842 Parameters act as local variables that are |
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1843 initialized with the argument values: |
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1844 |
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1845 <pre> |
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1846 parlist ::= namelist [‘<b>,</b>’ ‘<b>...</b>’] | ‘<b>...</b>’ |
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1847 </pre><p> |
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1848 When a function is called, |
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1849 the list of arguments is adjusted to |
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1850 the length of the list of parameters, |
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1851 unless the function is a <em>vararg function</em>, |
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1852 which is indicated by three dots ('<code>...</code>') |
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1853 at the end of its parameter list. |
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1854 A vararg function does not adjust its argument list; |
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1855 instead, it collects all extra arguments and supplies them |
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1856 to the function through a <em>vararg expression</em>, |
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1857 which is also written as three dots. |
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1858 The value of this expression is a list of all actual extra arguments, |
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1859 similar to a function with multiple results. |
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1860 If a vararg expression is used inside another expression |
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1861 or in the middle of a list of expressions, |
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1862 then its return list is adjusted to one element. |
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1863 If the expression is used as the last element of a list of expressions, |
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1864 then no adjustment is made |
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1865 (unless that last expression is enclosed in parentheses). |
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1866 |
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1867 |
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1868 <p> |
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1869 As an example, consider the following definitions: |
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1870 |
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1871 <pre> |
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1872 function f(a, b) end |
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1873 function g(a, b, ...) end |
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1874 function r() return 1,2,3 end |
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1875 </pre><p> |
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1876 Then, we have the following mapping from arguments to parameters and |
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1877 to the vararg expression: |
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1878 |
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|
1879 <pre> |
|
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|
1880 CALL PARAMETERS |
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1881 |
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1882 f(3) a=3, b=nil |
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1883 f(3, 4) a=3, b=4 |
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1884 f(3, 4, 5) a=3, b=4 |
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1885 f(r(), 10) a=1, b=10 |
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1886 f(r()) a=1, b=2 |
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1887 |
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1888 g(3) a=3, b=nil, ... --> (nothing) |
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1889 g(3, 4) a=3, b=4, ... --> (nothing) |
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1890 g(3, 4, 5, 8) a=3, b=4, ... --> 5 8 |
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1891 g(5, r()) a=5, b=1, ... --> 2 3 |
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1892 </pre> |
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1893 |
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1894 <p> |
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1895 Results are returned using the <b>return</b> statement (see <a href="#3.3.4">§3.3.4</a>). |
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1896 If control reaches the end of a function |
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1897 without encountering a <b>return</b> statement, |
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1898 then the function returns with no results. |
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1899 |
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1900 |
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|
1901 <p> |
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1902 |
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1903 There is a system-dependent limit on the number of values |
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1904 that a function may return. |
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1905 This limit is guaranteed to be larger than 1000. |
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1906 |
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1907 |
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1908 <p> |
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|
1909 The <em>colon</em> syntax |
|
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1910 is used for defining <em>methods</em>, |
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1911 that is, functions that have an implicit extra parameter <code>self</code>. |
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1912 Thus, the statement |
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1913 |
|
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|
1914 <pre> |
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1915 function t.a.b.c:f (<em>params</em>) <em>body</em> end |
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1916 </pre><p> |
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1917 is syntactic sugar for |
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1918 |
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1919 <pre> |
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1920 t.a.b.c.f = function (self, <em>params</em>) <em>body</em> end |
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1921 </pre> |
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1922 |
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1923 |
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1924 |
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1925 |
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1926 |
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1927 |
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1928 <h2>3.5 – <a name="3.5">Visibility Rules</a></h2> |
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1929 |
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1930 <p> |
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1931 |
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1932 Lua is a lexically scoped language. |
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1933 The scope of a local variable begins at the first statement after |
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1934 its declaration and lasts until the last non-void statement |
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1935 of the innermost block that includes the declaration. |
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1936 Consider the following example: |
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1937 |
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1938 <pre> |
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1939 x = 10 -- global variable |
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1940 do -- new block |
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1941 local x = x -- new 'x', with value 10 |
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1942 print(x) --> 10 |
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1943 x = x+1 |
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1944 do -- another block |
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1945 local x = x+1 -- another 'x' |
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1946 print(x) --> 12 |
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1947 end |
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1948 print(x) --> 11 |
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1949 end |
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1950 print(x) --> 10 (the global one) |
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1951 </pre> |
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1952 |
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1953 <p> |
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1954 Notice that, in a declaration like <code>local x = x</code>, |
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1955 the new <code>x</code> being declared is not in scope yet, |
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1956 and so the second <code>x</code> refers to the outside variable. |
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1957 |
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1958 |
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1959 <p> |
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1960 Because of the lexical scoping rules, |
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1961 local variables can be freely accessed by functions |
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1962 defined inside their scope. |
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1963 A local variable used by an inner function is called |
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1964 an <em>upvalue</em>, or <em>external local variable</em>, |
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1965 inside the inner function. |
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1966 |
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1967 |
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1968 <p> |
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1969 Notice that each execution of a <b>local</b> statement |
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1970 defines new local variables. |
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1971 Consider the following example: |
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1972 |
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1973 <pre> |
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1974 a = {} |
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1975 local x = 20 |
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1976 for i=1,10 do |
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1977 local y = 0 |
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1978 a[i] = function () y=y+1; return x+y end |
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1979 end |
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1980 </pre><p> |
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1981 The loop creates ten closures |
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1982 (that is, ten instances of the anonymous function). |
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1983 Each of these closures uses a different <code>y</code> variable, |
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1984 while all of them share the same <code>x</code>. |
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1985 |
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1986 |
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1987 |
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1988 |
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1989 |
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1990 <h1>4 – <a name="4">The Application Program Interface</a></h1> |
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1991 |
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1992 <p> |
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1993 |
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1994 This section describes the C API for Lua, that is, |
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1995 the set of C functions available to the host program to communicate |
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1996 with Lua. |
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1997 All API functions and related types and constants |
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1998 are declared in the header file <a name="pdf-lua.h"><code>lua.h</code></a>. |
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1999 |
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2000 |
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2001 <p> |
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2002 Even when we use the term "function", |
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2003 any facility in the API may be provided as a macro instead. |
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2004 Except where stated otherwise, |
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2005 all such macros use each of their arguments exactly once |
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2006 (except for the first argument, which is always a Lua state), |
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2007 and so do not generate any hidden side-effects. |
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2008 |
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2009 |
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2010 <p> |
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2011 As in most C libraries, |
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2012 the Lua API functions do not check their arguments for validity or consistency. |
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2013 However, you can change this behavior by compiling Lua |
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2014 with the macro <a name="pdf-LUA_USE_APICHECK"><code>LUA_USE_APICHECK</code></a> defined. |
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2015 |
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2016 |
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2017 |
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2018 <h2>4.1 – <a name="4.1">The Stack</a></h2> |
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2019 |
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2020 <p> |
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2021 Lua uses a <em>virtual stack</em> to pass values to and from C. |
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2022 Each element in this stack represents a Lua value |
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2023 (<b>nil</b>, number, string, etc.). |
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2024 |
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2025 |
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2026 <p> |
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2027 Whenever Lua calls C, the called function gets a new stack, |
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2028 which is independent of previous stacks and of stacks of |
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2029 C functions that are still active. |
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2030 This stack initially contains any arguments to the C function |
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2031 and it is where the C function pushes its results |
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2032 to be returned to the caller (see <a href="#lua_CFunction"><code>lua_CFunction</code></a>). |
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2033 |
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2034 |
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2035 <p> |
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2036 For convenience, |
|
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2037 most query operations in the API do not follow a strict stack discipline. |
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2038 Instead, they can refer to any element in the stack |
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2039 by using an <em>index</em>: |
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2040 A positive index represents an absolute stack position |
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2041 (starting at 1); |
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2042 a negative index represents an offset relative to the top of the stack. |
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2043 More specifically, if the stack has <em>n</em> elements, |
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2044 then index 1 represents the first element |
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2045 (that is, the element that was pushed onto the stack first) |
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2046 and |
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2047 index <em>n</em> represents the last element; |
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2048 index -1 also represents the last element |
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2049 (that is, the element at the top) |
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2050 and index <em>-n</em> represents the first element. |
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2051 |
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2052 |
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2053 |
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2054 |
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2055 |
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2056 <h2>4.2 – <a name="4.2">Stack Size</a></h2> |
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2057 |
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2058 <p> |
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2059 When you interact with the Lua API, |
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2060 you are responsible for ensuring consistency. |
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2061 In particular, |
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2062 <em>you are responsible for controlling stack overflow</em>. |
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2063 You can use the function <a href="#lua_checkstack"><code>lua_checkstack</code></a> |
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2064 to ensure that the stack has enough space for pushing new elements. |
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2065 |
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2066 |
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2067 <p> |
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2068 Whenever Lua calls C, |
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2069 it ensures that the stack has space for |
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2070 at least <a name="pdf-LUA_MINSTACK"><code>LUA_MINSTACK</code></a> extra slots. |
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2071 <code>LUA_MINSTACK</code> is defined as 20, |
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2072 so that usually you do not have to worry about stack space |
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2073 unless your code has loops pushing elements onto the stack. |
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2074 |
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2075 |
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2076 <p> |
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2077 When you call a Lua function |
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2078 without a fixed number of results (see <a href="#lua_call"><code>lua_call</code></a>), |
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2079 Lua ensures that the stack has enough space for all results, |
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2080 but it does not ensure any extra space. |
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2081 So, before pushing anything in the stack after such a call |
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2082 you should use <a href="#lua_checkstack"><code>lua_checkstack</code></a>. |
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2083 |
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2084 |
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2085 |
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2086 |
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2087 |
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2088 <h2>4.3 – <a name="4.3">Valid and Acceptable Indices</a></h2> |
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2089 |
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2090 <p> |
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2091 Any function in the API that receives stack indices |
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2092 works only with <em>valid indices</em> or <em>acceptable indices</em>. |
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2093 |
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2094 |
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2095 <p> |
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2096 A <em>valid index</em> is an index that refers to a |
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2097 real position within the stack, that is, |
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2098 its position lies between 1 and the stack top |
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2099 (<code>1 ≤ abs(index) ≤ top</code>). |
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2100 |
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2101 Usually, functions that can modify the value at an index |
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2102 require valid indices. |
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2103 |
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2104 |
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2105 <p> |
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2106 Unless otherwise noted, |
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2107 any function that accepts valid indices also accepts <em>pseudo-indices</em>, |
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2108 which represent some Lua values that are accessible to C code |
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2109 but which are not in the stack. |
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2110 Pseudo-indices are used to access the registry |
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2111 and the upvalues of a C function (see <a href="#4.4">§4.4</a>). |
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2112 |
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2113 |
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2114 <p> |
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2115 Functions that do not need a specific stack position, |
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2116 but only a value in the stack (e.g., query functions), |
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2117 can be called with acceptable indices. |
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2118 An <em>acceptable index</em> can be any valid index, |
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2119 including the pseudo-indices, |
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2120 but it also can be any positive index after the stack top |
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2121 within the space allocated for the stack, |
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2122 that is, indices up to the stack size. |
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2123 (Note that 0 is never an acceptable index.) |
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2124 Except when noted otherwise, |
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2125 functions in the API work with acceptable indices. |
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2126 |
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2127 |
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2128 <p> |
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2129 Acceptable indices serve to avoid extra tests |
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2130 against the stack top when querying the stack. |
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2131 For instance, a C function can query its third argument |
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2132 without the need to first check whether there is a third argument, |
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2133 that is, without the need to check whether 3 is a valid index. |
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2134 |
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2135 |
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2136 <p> |
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2137 For functions that can be called with acceptable indices, |
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2138 any non-valid index is treated as if it |
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2139 contains a value of a virtual type <a name="pdf-LUA_TNONE"><code>LUA_TNONE</code></a>, |
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2140 which behaves like a nil value. |
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2141 |
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2142 |
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2143 |
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2144 |
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2145 |
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2146 <h2>4.4 – <a name="4.4">C Closures</a></h2> |
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2147 |
|
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2148 <p> |
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2149 When a C function is created, |
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2150 it is possible to associate some values with it, |
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2151 thus creating a <em>C closure</em> |
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2152 (see <a href="#lua_pushcclosure"><code>lua_pushcclosure</code></a>); |
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2153 these values are called <em>upvalues</em> and are |
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2154 accessible to the function whenever it is called. |
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2155 |
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2156 |
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2157 <p> |
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2158 Whenever a C function is called, |
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2159 its upvalues are located at specific pseudo-indices. |
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2160 These pseudo-indices are produced by the macro |
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2161 <a href="#lua_upvalueindex"><code>lua_upvalueindex</code></a>. |
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2162 The first value associated with a function is at position |
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2163 <code>lua_upvalueindex(1)</code>, and so on. |
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2164 Any access to <code>lua_upvalueindex(<em>n</em>)</code>, |
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2165 where <em>n</em> is greater than the number of upvalues of the |
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2166 current function (but not greater than 256), |
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2167 produces an acceptable but invalid index. |
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2168 |
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2169 |
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2170 |
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2171 |
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2172 |
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2173 <h2>4.5 – <a name="4.5">Registry</a></h2> |
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2174 |
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2175 <p> |
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2176 Lua provides a <em>registry</em>, |
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2177 a predefined table that can be used by any C code to |
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2178 store whatever Lua values it needs to store. |
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2179 The registry table is always located at pseudo-index |
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2180 <a name="pdf-LUA_REGISTRYINDEX"><code>LUA_REGISTRYINDEX</code></a>, |
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2181 which is a valid index. |
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2182 Any C library can store data into this table, |
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2183 but it must take care to choose keys |
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2184 that are different from those used |
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2185 by other libraries, to avoid collisions. |
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2186 Typically, you should use as key a string containing your library name, |
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2187 or a light userdata with the address of a C object in your code, |
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2188 or any Lua object created by your code. |
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2189 As with variable names, |
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2190 string keys starting with an underscore followed by |
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2191 uppercase letters are reserved for Lua. |
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2192 |
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2193 |
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2194 <p> |
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2195 The integer keys in the registry are used |
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2196 by the reference mechanism (see <a href="#luaL_ref"><code>luaL_ref</code></a>) |
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2197 and by some predefined values. |
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2198 Therefore, integer keys must not be used for other purposes. |
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2199 |
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2200 |
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2201 <p> |
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2202 When you create a new Lua state, |
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2203 its registry comes with some predefined values. |
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2204 These predefined values are indexed with integer keys |
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2205 defined as constants in <code>lua.h</code>. |
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2206 The following constants are defined: |
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2207 |
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2208 <ul> |
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2209 <li><b><a name="pdf-LUA_RIDX_MAINTHREAD"><code>LUA_RIDX_MAINTHREAD</code></a>: </b> At this index the registry has |
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2210 the main thread of the state. |
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2211 (The main thread is the one created together with the state.) |
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2212 </li> |
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2213 |
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2214 <li><b><a name="pdf-LUA_RIDX_GLOBALS"><code>LUA_RIDX_GLOBALS</code></a>: </b> At this index the registry has |
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2215 the global environment. |
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2216 </li> |
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2217 </ul> |
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2218 |
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2219 |
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2220 |
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2221 |
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2222 <h2>4.6 – <a name="4.6">Error Handling in C</a></h2> |
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2223 |
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2224 <p> |
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2225 Internally, Lua uses the C <code>longjmp</code> facility to handle errors. |
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2226 (Lua will use exceptions if you compile it as C++; |
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2227 search for <code>LUAI_THROW</code> in the source code for details.) |
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2228 When Lua faces any error |
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2229 (such as a memory allocation error, type errors, syntax errors, |
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2230 and runtime errors) |
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2231 it <em>raises</em> an error; |
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2232 that is, it does a long jump. |
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2233 A <em>protected environment</em> uses <code>setjmp</code> |
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2234 to set a recovery point; |
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2235 any error jumps to the most recent active recovery point. |
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2236 |
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2237 |
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2238 <p> |
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2239 If an error happens outside any protected environment, |
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2240 Lua calls a <em>panic function</em> (see <a href="#lua_atpanic"><code>lua_atpanic</code></a>) |
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2241 and then calls <code>abort</code>, |
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2242 thus exiting the host application. |
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2243 Your panic function can avoid this exit by |
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2244 never returning |
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2245 (e.g., doing a long jump to your own recovery point outside Lua). |
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2246 |
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2247 |
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2248 <p> |
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2249 The panic function runs as if it were a message handler (see <a href="#2.3">§2.3</a>); |
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2250 in particular, the error message is at the top of the stack. |
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2251 However, there is no guarantee about stack space. |
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2252 To push anything on the stack, |
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2253 the panic function must first check the available space (see <a href="#4.2">§4.2</a>). |
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2254 |
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2255 |
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2256 <p> |
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2257 Most functions in the API can raise an error, |
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2258 for instance due to a memory allocation error. |
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2259 The documentation for each function indicates whether |
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2260 it can raise errors. |
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2261 |
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2262 |
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2263 <p> |
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2264 Inside a C function you can raise an error by calling <a href="#lua_error"><code>lua_error</code></a>. |
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2265 |
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2266 |
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2267 |
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2268 |
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2269 |
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2270 <h2>4.7 – <a name="4.7">Handling Yields in C</a></h2> |
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2271 |
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2272 <p> |
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2273 Internally, Lua uses the C <code>longjmp</code> facility to yield a coroutine. |
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2274 Therefore, if a C function <code>foo</code> calls an API function |
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2275 and this API function yields |
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2276 (directly or indirectly by calling another function that yields), |
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2277 Lua cannot return to <code>foo</code> any more, |
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2278 because the <code>longjmp</code> removes its frame from the C stack. |
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2279 |
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2280 |
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2281 <p> |
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2282 To avoid this kind of problem, |
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2283 Lua raises an error whenever it tries to yield across an API call, |
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2284 except for three functions: |
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2285 <a href="#lua_yieldk"><code>lua_yieldk</code></a>, <a href="#lua_callk"><code>lua_callk</code></a>, and <a href="#lua_pcallk"><code>lua_pcallk</code></a>. |
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2286 All those functions receive a <em>continuation function</em> |
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2287 (as a parameter named <code>k</code>) to continue execution after a yield. |
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2288 |
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2289 |
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2290 <p> |
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2291 We need to set some terminology to explain continuations. |
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2292 We have a C function called from Lua which we will call |
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2293 the <em>original function</em>. |
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2294 This original function then calls one of those three functions in the C API, |
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2295 which we will call the <em>callee function</em>, |
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2296 that then yields the current thread. |
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2297 (This can happen when the callee function is <a href="#lua_yieldk"><code>lua_yieldk</code></a>, |
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2298 or when the callee function is either <a href="#lua_callk"><code>lua_callk</code></a> or <a href="#lua_pcallk"><code>lua_pcallk</code></a> |
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2299 and the function called by them yields.) |
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2300 |
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2301 |
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2302 <p> |
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2303 Suppose the running thread yields while executing the callee function. |
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2304 After the thread resumes, |
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2305 it eventually will finish running the callee function. |
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2306 However, |
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2307 the callee function cannot return to the original function, |
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2308 because its frame in the C stack was destroyed by the yield. |
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2309 Instead, Lua calls a <em>continuation function</em>, |
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2310 which was given as an argument to the callee function. |
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2311 As the name implies, |
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2312 the continuation function should continue the task |
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2313 of the original function. |
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2314 |
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2315 |
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2316 <p> |
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2317 As an illustration, consider the following function: |
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2318 |
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2319 <pre> |
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2320 int original_function (lua_State *L) { |
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2321 ... /* code 1 */ |
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2322 status = lua_pcall(L, n, m, h); /* calls Lua */ |
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2323 ... /* code 2 */ |
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2324 } |
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2325 </pre><p> |
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2326 Now we want to allow |
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2327 the Lua code being run by <a href="#lua_pcall"><code>lua_pcall</code></a> to yield. |
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2328 First, we can rewrite our function like here: |
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2329 |
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2330 <pre> |
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2331 int k (lua_State *L, int status, lua_KContext ctx) { |
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2332 ... /* code 2 */ |
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2333 } |
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2334 |
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2335 int original_function (lua_State *L) { |
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2336 ... /* code 1 */ |
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2337 return k(L, lua_pcall(L, n, m, h), ctx); |
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2338 } |
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2339 </pre><p> |
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2340 In the above code, |
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2341 the new function <code>k</code> is a |
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2342 <em>continuation function</em> (with type <a href="#lua_KFunction"><code>lua_KFunction</code></a>), |
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2343 which should do all the work that the original function |
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2344 was doing after calling <a href="#lua_pcall"><code>lua_pcall</code></a>. |
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2345 Now, we must inform Lua that it must call <code>k</code> if the Lua code |
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2346 being executed by <a href="#lua_pcall"><code>lua_pcall</code></a> gets interrupted in some way |
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2347 (errors or yielding), |
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2348 so we rewrite the code as here, |
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2349 replacing <a href="#lua_pcall"><code>lua_pcall</code></a> by <a href="#lua_pcallk"><code>lua_pcallk</code></a>: |
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2350 |
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2351 <pre> |
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2352 int original_function (lua_State *L) { |
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2353 ... /* code 1 */ |
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2354 return k(L, lua_pcallk(L, n, m, h, ctx2, k), ctx1); |
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2355 } |
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2356 </pre><p> |
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2357 Note the external, explicit call to the continuation: |
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2358 Lua will call the continuation only if needed, that is, |
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2359 in case of errors or resuming after a yield. |
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2360 If the called function returns normally without ever yielding, |
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2361 <a href="#lua_pcallk"><code>lua_pcallk</code></a> (and <a href="#lua_callk"><code>lua_callk</code></a>) will also return normally. |
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2362 (Of course, instead of calling the continuation in that case, |
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2363 you can do the equivalent work directly inside the original function.) |
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2364 |
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2365 |
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2366 <p> |
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2367 Besides the Lua state, |
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2368 the continuation function has two other parameters: |
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2369 the final status of the call plus the context value (<code>ctx</code>) that |
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2370 was passed originally to <a href="#lua_pcallk"><code>lua_pcallk</code></a>. |
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2371 (Lua does not use this context value; |
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2372 it only passes this value from the original function to the |
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2373 continuation function.) |
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2374 For <a href="#lua_pcallk"><code>lua_pcallk</code></a>, |
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2375 the status is the same value that would be returned by <a href="#lua_pcallk"><code>lua_pcallk</code></a>, |
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2376 except that it is <a href="#pdf-LUA_YIELD"><code>LUA_YIELD</code></a> when being executed after a yield |
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2377 (instead of <a href="#pdf-LUA_OK"><code>LUA_OK</code></a>). |
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2378 For <a href="#lua_yieldk"><code>lua_yieldk</code></a> and <a href="#lua_callk"><code>lua_callk</code></a>, |
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2379 the status is always <a href="#pdf-LUA_YIELD"><code>LUA_YIELD</code></a> when Lua calls the continuation. |
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2380 (For these two functions, |
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2381 Lua will not call the continuation in case of errors, |
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2382 because they do not handle errors.) |
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2383 Similarly, when using <a href="#lua_callk"><code>lua_callk</code></a>, |
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|
2384 you should call the continuation function |
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2385 with <a href="#pdf-LUA_OK"><code>LUA_OK</code></a> as the status. |
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2386 (For <a href="#lua_yieldk"><code>lua_yieldk</code></a>, there is not much point in calling |
|
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2387 directly the continuation function, |
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2388 because <a href="#lua_yieldk"><code>lua_yieldk</code></a> usually does not return.) |
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2389 |
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2390 |
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2391 <p> |
|
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2392 Lua treats the continuation function as if it were the original function. |
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2393 The continuation function receives the same Lua stack |
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2394 from the original function, |
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2395 in the same state it would be if the callee function had returned. |
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2396 (For instance, |
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2397 after a <a href="#lua_callk"><code>lua_callk</code></a> the function and its arguments are |
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2398 removed from the stack and replaced by the results from the call.) |
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2399 It also has the same upvalues. |
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2400 Whatever it returns is handled by Lua as if it were the return |
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2401 of the original function. |
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2402 |
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2403 |
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2404 |
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2405 |
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2406 |
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2407 <h2>4.8 – <a name="4.8">Functions and Types</a></h2> |
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2408 |
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2409 <p> |
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2410 Here we list all functions and types from the C API in |
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2411 alphabetical order. |
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2412 Each function has an indicator like this: |
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2413 <span class="apii">[-o, +p, <em>x</em>]</span> |
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2414 |
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2415 |
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2416 <p> |
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2417 The first field, <code>o</code>, |
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2418 is how many elements the function pops from the stack. |
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2419 The second field, <code>p</code>, |
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2420 is how many elements the function pushes onto the stack. |
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2421 (Any function always pushes its results after popping its arguments.) |
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2422 A field in the form <code>x|y</code> means the function can push (or pop) |
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2423 <code>x</code> or <code>y</code> elements, |
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2424 depending on the situation; |
|
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2425 an interrogation mark '<code>?</code>' means that |
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2426 we cannot know how many elements the function pops/pushes |
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2427 by looking only at its arguments |
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2428 (e.g., they may depend on what is on the stack). |
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2429 The third field, <code>x</code>, |
|
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2430 tells whether the function may raise errors: |
|
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2431 '<code>-</code>' means the function never raises any error; |
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2432 '<code>e</code>' means the function may raise errors; |
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2433 '<code>v</code>' means the function may raise an error on purpose. |
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2434 |
|
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2435 |
|
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2436 |
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2437 <hr><h3><a name="lua_absindex"><code>lua_absindex</code></a></h3><p> |
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2438 <span class="apii">[-0, +0, –]</span> |
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2439 <pre>int lua_absindex (lua_State *L, int idx);</pre> |
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2440 |
|
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2441 <p> |
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2442 Converts the acceptable index <code>idx</code> into an absolute index |
|
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2443 (that is, one that does not depend on the stack top). |
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2444 |
|
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2445 |
|
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2446 |
|
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2447 |
|
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2448 |
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2449 <hr><h3><a name="lua_Alloc"><code>lua_Alloc</code></a></h3> |
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2450 <pre>typedef void * (*lua_Alloc) (void *ud, |
|
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2451 void *ptr, |
|
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2452 size_t osize, |
|
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|
2453 size_t nsize);</pre> |
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2454 |
|
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|
2455 <p> |
|
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|
2456 The type of the memory-allocation function used by Lua states. |
|
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|
2457 The allocator function must provide a |
|
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2458 functionality similar to <code>realloc</code>, |
|
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2459 but not exactly the same. |
|
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|
2460 Its arguments are |
|
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|
2461 <code>ud</code>, an opaque pointer passed to <a href="#lua_newstate"><code>lua_newstate</code></a>; |
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2462 <code>ptr</code>, a pointer to the block being allocated/reallocated/freed; |
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2463 <code>osize</code>, the original size of the block or some code about what |
|
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2464 is being allocated; |
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2465 and <code>nsize</code>, the new size of the block. |
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2466 |
|
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2467 |
|
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2468 <p> |
|
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|
2469 When <code>ptr</code> is not <code>NULL</code>, |
|
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|
2470 <code>osize</code> is the size of the block pointed by <code>ptr</code>, |
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2471 that is, the size given when it was allocated or reallocated. |
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2472 |
|
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2473 |
|
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2474 <p> |
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2475 When <code>ptr</code> is <code>NULL</code>, |
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2476 <code>osize</code> encodes the kind of object that Lua is allocating. |
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2477 <code>osize</code> is any of |
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2478 <a href="#pdf-LUA_TSTRING"><code>LUA_TSTRING</code></a>, <a href="#pdf-LUA_TTABLE"><code>LUA_TTABLE</code></a>, <a href="#pdf-LUA_TFUNCTION"><code>LUA_TFUNCTION</code></a>, |
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2479 <a href="#pdf-LUA_TUSERDATA"><code>LUA_TUSERDATA</code></a>, or <a href="#pdf-LUA_TTHREAD"><code>LUA_TTHREAD</code></a> when (and only when) |
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2480 Lua is creating a new object of that type. |
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2481 When <code>osize</code> is some other value, |
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2482 Lua is allocating memory for something else. |
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2483 |
|
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2484 |
|
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2485 <p> |
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2486 Lua assumes the following behavior from the allocator function: |
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2487 |
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2488 |
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2489 <p> |
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2490 When <code>nsize</code> is zero, |
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2491 the allocator must behave like <code>free</code> |
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2492 and return <code>NULL</code>. |
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2493 |
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2494 |
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2495 <p> |
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2496 When <code>nsize</code> is not zero, |
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2497 the allocator must behave like <code>realloc</code>. |
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2498 The allocator returns <code>NULL</code> |
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2499 if and only if it cannot fulfill the request. |
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2500 Lua assumes that the allocator never fails when |
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2501 <code>osize >= nsize</code>. |
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2502 |
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2503 |
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2504 <p> |
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2505 Here is a simple implementation for the allocator function. |
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2506 It is used in the auxiliary library by <a href="#luaL_newstate"><code>luaL_newstate</code></a>. |
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2507 |
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2508 <pre> |
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2509 static void *l_alloc (void *ud, void *ptr, size_t osize, |
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2510 size_t nsize) { |
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2511 (void)ud; (void)osize; /* not used */ |
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2512 if (nsize == 0) { |
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2513 free(ptr); |
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2514 return NULL; |
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2515 } |
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2516 else |
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2517 return realloc(ptr, nsize); |
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2518 } |
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2519 </pre><p> |
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2520 Note that Standard C ensures |
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2521 that <code>free(NULL)</code> has no effect and that |
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2522 <code>realloc(NULL,size)</code> is equivalent to <code>malloc(size)</code>. |
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2523 This code assumes that <code>realloc</code> does not fail when shrinking a block. |
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2524 (Although Standard C does not ensure this behavior, |
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2525 it seems to be a safe assumption.) |
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2526 |
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2527 |
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2528 |
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2529 |
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2530 |
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2531 <hr><h3><a name="lua_arith"><code>lua_arith</code></a></h3><p> |
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2532 <span class="apii">[-(2|1), +1, <em>e</em>]</span> |
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2533 <pre>void lua_arith (lua_State *L, int op);</pre> |
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2534 |
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2535 <p> |
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2536 Performs an arithmetic or bitwise operation over the two values |
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2537 (or one, in the case of negations) |
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2538 at the top of the stack, |
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2539 with the value at the top being the second operand, |
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2540 pops these values, and pushes the result of the operation. |
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2541 The function follows the semantics of the corresponding Lua operator |
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2542 (that is, it may call metamethods). |
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2543 |
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2544 |
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2545 <p> |
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2546 The value of <code>op</code> must be one of the following constants: |
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2547 |
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2548 <ul> |
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2549 |
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2550 <li><b><a name="pdf-LUA_OPADD"><code>LUA_OPADD</code></a>: </b> performs addition (<code>+</code>)</li> |
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2551 <li><b><a name="pdf-LUA_OPSUB"><code>LUA_OPSUB</code></a>: </b> performs subtraction (<code>-</code>)</li> |
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2552 <li><b><a name="pdf-LUA_OPMUL"><code>LUA_OPMUL</code></a>: </b> performs multiplication (<code>*</code>)</li> |
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2553 <li><b><a name="pdf-LUA_OPDIV"><code>LUA_OPDIV</code></a>: </b> performs float division (<code>/</code>)</li> |
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2554 <li><b><a name="pdf-LUA_OPIDIV"><code>LUA_OPIDIV</code></a>: </b> performs floor division (<code>//</code>)</li> |
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2555 <li><b><a name="pdf-LUA_OPMOD"><code>LUA_OPMOD</code></a>: </b> performs modulo (<code>%</code>)</li> |
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2556 <li><b><a name="pdf-LUA_OPPOW"><code>LUA_OPPOW</code></a>: </b> performs exponentiation (<code>^</code>)</li> |
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2557 <li><b><a name="pdf-LUA_OPUNM"><code>LUA_OPUNM</code></a>: </b> performs mathematical negation (unary <code>-</code>)</li> |
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2558 <li><b><a name="pdf-LUA_OPBNOT"><code>LUA_OPBNOT</code></a>: </b> performs bitwise negation (<code>~</code>)</li> |
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2559 <li><b><a name="pdf-LUA_OPBAND"><code>LUA_OPBAND</code></a>: </b> performs bitwise and (<code>&</code>)</li> |
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2560 <li><b><a name="pdf-LUA_OPBOR"><code>LUA_OPBOR</code></a>: </b> performs bitwise or (<code>|</code>)</li> |
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2561 <li><b><a name="pdf-LUA_OPBXOR"><code>LUA_OPBXOR</code></a>: </b> performs bitwise exclusive or (<code>~</code>)</li> |
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2562 <li><b><a name="pdf-LUA_OPSHL"><code>LUA_OPSHL</code></a>: </b> performs left shift (<code><<</code>)</li> |
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2563 <li><b><a name="pdf-LUA_OPSHR"><code>LUA_OPSHR</code></a>: </b> performs right shift (<code>>></code>)</li> |
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2564 |
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2565 </ul> |
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2566 |
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2567 |
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2568 |
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2569 |
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2570 <hr><h3><a name="lua_atpanic"><code>lua_atpanic</code></a></h3><p> |
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2571 <span class="apii">[-0, +0, –]</span> |
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2572 <pre>lua_CFunction lua_atpanic (lua_State *L, lua_CFunction panicf);</pre> |
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2573 |
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2574 <p> |
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2575 Sets a new panic function and returns the old one (see <a href="#4.6">§4.6</a>). |
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2576 |
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2577 |
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2578 |
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2579 |
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2580 |
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2581 <hr><h3><a name="lua_call"><code>lua_call</code></a></h3><p> |
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2582 <span class="apii">[-(nargs+1), +nresults, <em>e</em>]</span> |
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2583 <pre>void lua_call (lua_State *L, int nargs, int nresults);</pre> |
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2584 |
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2585 <p> |
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2586 Calls a function. |
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2587 |
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2588 |
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2589 <p> |
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2590 To call a function you must use the following protocol: |
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2591 first, the function to be called is pushed onto the stack; |
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2592 then, the arguments to the function are pushed |
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2593 in direct order; |
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2594 that is, the first argument is pushed first. |
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2595 Finally you call <a href="#lua_call"><code>lua_call</code></a>; |
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2596 <code>nargs</code> is the number of arguments that you pushed onto the stack. |
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2597 All arguments and the function value are popped from the stack |
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2598 when the function is called. |
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2599 The function results are pushed onto the stack when the function returns. |
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2600 The number of results is adjusted to <code>nresults</code>, |
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2601 unless <code>nresults</code> is <a name="pdf-LUA_MULTRET"><code>LUA_MULTRET</code></a>. |
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2602 In this case, all results from the function are pushed. |
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2603 Lua takes care that the returned values fit into the stack space. |
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2604 The function results are pushed onto the stack in direct order |
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2605 (the first result is pushed first), |
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2606 so that after the call the last result is on the top of the stack. |
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2607 |
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2608 |
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2609 <p> |
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2610 Any error inside the called function is propagated upwards |
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2611 (with a <code>longjmp</code>). |
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2612 |
|
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2613 |
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2614 <p> |
|
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2615 The following example shows how the host program can do the |
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2616 equivalent to this Lua code: |
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2617 |
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|
2618 <pre> |
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2619 a = f("how", t.x, 14) |
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2620 </pre><p> |
|
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2621 Here it is in C: |
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2622 |
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|
2623 <pre> |
|
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2624 lua_getglobal(L, "f"); /* function to be called */ |
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2625 lua_pushliteral(L, "how"); /* 1st argument */ |
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2626 lua_getglobal(L, "t"); /* table to be indexed */ |
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2627 lua_getfield(L, -1, "x"); /* push result of t.x (2nd arg) */ |
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2628 lua_remove(L, -2); /* remove 't' from the stack */ |
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2629 lua_pushinteger(L, 14); /* 3rd argument */ |
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2630 lua_call(L, 3, 1); /* call 'f' with 3 arguments and 1 result */ |
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2631 lua_setglobal(L, "a"); /* set global 'a' */ |
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2632 </pre><p> |
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2633 Note that the code above is <em>balanced</em>: |
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2634 at its end, the stack is back to its original configuration. |
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2635 This is considered good programming practice. |
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2636 |
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2637 |
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2638 |
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2639 |
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2640 |
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2641 <hr><h3><a name="lua_callk"><code>lua_callk</code></a></h3><p> |
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|
2642 <span class="apii">[-(nargs + 1), +nresults, <em>e</em>]</span> |
|
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2643 <pre>void lua_callk (lua_State *L, |
|
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2644 int nargs, |
|
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2645 int nresults, |
|
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2646 lua_KContext ctx, |
|
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|
2647 lua_KFunction k);</pre> |
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2648 |
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2649 <p> |
|
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|
2650 This function behaves exactly like <a href="#lua_call"><code>lua_call</code></a>, |
|
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2651 but allows the called function to yield (see <a href="#4.7">§4.7</a>). |
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2652 |
|
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|
2653 |
|
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|
2654 |
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2655 |
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2656 |
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|
2657 <hr><h3><a name="lua_CFunction"><code>lua_CFunction</code></a></h3> |
|
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|
2658 <pre>typedef int (*lua_CFunction) (lua_State *L);</pre> |
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2659 |
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2660 <p> |
|
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|
2661 Type for C functions. |
|
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2662 |
|
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2663 |
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2664 <p> |
|
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|
2665 In order to communicate properly with Lua, |
|
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|
2666 a C function must use the following protocol, |
|
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2667 which defines the way parameters and results are passed: |
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2668 a C function receives its arguments from Lua in its stack |
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2669 in direct order (the first argument is pushed first). |
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|
2670 So, when the function starts, |
|
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|
2671 <code>lua_gettop(L)</code> returns the number of arguments received by the function. |
|
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|
2672 The first argument (if any) is at index 1 |
|
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|
2673 and its last argument is at index <code>lua_gettop(L)</code>. |
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|
2674 To return values to Lua, a C function just pushes them onto the stack, |
|
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|
2675 in direct order (the first result is pushed first), |
|
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2676 and returns the number of results. |
|
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|
2677 Any other value in the stack below the results will be properly |
|
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|
2678 discarded by Lua. |
|
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|
2679 Like a Lua function, a C function called by Lua can also return |
|
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2680 many results. |
|
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|
2681 |
|
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|
2682 |
|
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|
2683 <p> |
|
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|
2684 As an example, the following function receives a variable number |
|
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|
2685 of numerical arguments and returns their average and their sum: |
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2686 |
|
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|
2687 <pre> |
|
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2688 static int foo (lua_State *L) { |
|
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2689 int n = lua_gettop(L); /* number of arguments */ |
|
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|
2690 lua_Number sum = 0.0; |
|
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|
2691 int i; |
|
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|
2692 for (i = 1; i <= n; i++) { |
|
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|
2693 if (!lua_isnumber(L, i)) { |
|
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|
2694 lua_pushliteral(L, "incorrect argument"); |
|
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|
2695 lua_error(L); |
|
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|
2696 } |
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2697 sum += lua_tonumber(L, i); |
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2698 } |
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2699 lua_pushnumber(L, sum/n); /* first result */ |
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2700 lua_pushnumber(L, sum); /* second result */ |
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|
2701 return 2; /* number of results */ |
|
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|
2702 } |
|
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|
2703 </pre> |
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2704 |
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|
2705 |
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2706 |
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|
2707 |
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|
2708 <hr><h3><a name="lua_checkstack"><code>lua_checkstack</code></a></h3><p> |
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2709 <span class="apii">[-0, +0, –]</span> |
|
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2710 <pre>int lua_checkstack (lua_State *L, int n);</pre> |
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2711 |
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2712 <p> |
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|
2713 Ensures that the stack has space for at least <code>n</code> extra slots. |
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2714 It returns false if it cannot fulfill the request, |
|
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|
2715 either because it would cause the stack |
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2716 to be larger than a fixed maximum size |
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2717 (typically at least several thousand elements) or |
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2718 because it cannot allocate memory for the extra space. |
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2719 This function never shrinks the stack; |
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2720 if the stack is already larger than the new size, |
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2721 it is left unchanged. |
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2722 |
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2723 |
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2724 |
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2725 |
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|
2726 |
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2727 <hr><h3><a name="lua_close"><code>lua_close</code></a></h3><p> |
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2728 <span class="apii">[-0, +0, –]</span> |
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2729 <pre>void lua_close (lua_State *L);</pre> |
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2730 |
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2731 <p> |
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2732 Destroys all objects in the given Lua state |
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2733 (calling the corresponding garbage-collection metamethods, if any) |
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2734 and frees all dynamic memory used by this state. |
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2735 On several platforms, you may not need to call this function, |
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2736 because all resources are naturally released when the host program ends. |
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2737 On the other hand, long-running programs that create multiple states, |
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2738 such as daemons or web servers, |
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2739 will probably need to close states as soon as they are not needed. |
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2740 |
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2741 |
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2742 |
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2743 |
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2744 |
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2745 <hr><h3><a name="lua_compare"><code>lua_compare</code></a></h3><p> |
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2746 <span class="apii">[-0, +0, <em>e</em>]</span> |
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2747 <pre>int lua_compare (lua_State *L, int index1, int index2, int op);</pre> |
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2748 |
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2749 <p> |
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2750 Compares two Lua values. |
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2751 Returns 1 if the value at index <code>index1</code> satisfies <code>op</code> |
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2752 when compared with the value at index <code>index2</code>, |
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2753 following the semantics of the corresponding Lua operator |
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2754 (that is, it may call metamethods). |
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2755 Otherwise returns 0. |
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2756 Also returns 0 if any of the indices is not valid. |
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2757 |
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2758 |
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2759 <p> |
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2760 The value of <code>op</code> must be one of the following constants: |
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2761 |
|
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2762 <ul> |
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2763 |
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2764 <li><b><a name="pdf-LUA_OPEQ"><code>LUA_OPEQ</code></a>: </b> compares for equality (<code>==</code>)</li> |
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2765 <li><b><a name="pdf-LUA_OPLT"><code>LUA_OPLT</code></a>: </b> compares for less than (<code><</code>)</li> |
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2766 <li><b><a name="pdf-LUA_OPLE"><code>LUA_OPLE</code></a>: </b> compares for less or equal (<code><=</code>)</li> |
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2767 |
|
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|
2768 </ul> |
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2769 |
|
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2770 |
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2771 |
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2772 |
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2773 <hr><h3><a name="lua_concat"><code>lua_concat</code></a></h3><p> |
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2774 <span class="apii">[-n, +1, <em>e</em>]</span> |
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2775 <pre>void lua_concat (lua_State *L, int n);</pre> |
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2776 |
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2777 <p> |
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2778 Concatenates the <code>n</code> values at the top of the stack, |
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2779 pops them, and leaves the result at the top. |
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2780 If <code>n</code> is 1, the result is the single value on the stack |
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2781 (that is, the function does nothing); |
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2782 if <code>n</code> is 0, the result is the empty string. |
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2783 Concatenation is performed following the usual semantics of Lua |
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2784 (see <a href="#3.4.6">§3.4.6</a>). |
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|
2785 |
|
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|
2786 |
|
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2787 |
|
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2788 |
|
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2789 |
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2790 <hr><h3><a name="lua_copy"><code>lua_copy</code></a></h3><p> |
|
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2791 <span class="apii">[-0, +0, –]</span> |
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2792 <pre>void lua_copy (lua_State *L, int fromidx, int toidx);</pre> |
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2793 |
|
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|
2794 <p> |
|
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2795 Copies the element at index <code>fromidx</code> |
|
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2796 into the valid index <code>toidx</code>, |
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2797 replacing the value at that position. |
|
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2798 Values at other positions are not affected. |
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2799 |
|
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|
2800 |
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2801 |
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2802 |
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2803 |
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|
2804 <hr><h3><a name="lua_createtable"><code>lua_createtable</code></a></h3><p> |
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|
2805 <span class="apii">[-0, +1, <em>e</em>]</span> |
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|
2806 <pre>void lua_createtable (lua_State *L, int narr, int nrec);</pre> |
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2807 |
|
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2808 <p> |
|
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2809 Creates a new empty table and pushes it onto the stack. |
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2810 Parameter <code>narr</code> is a hint for how many elements the table |
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2811 will have as a sequence; |
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|
2812 parameter <code>nrec</code> is a hint for how many other elements |
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2813 the table will have. |
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2814 Lua may use these hints to preallocate memory for the new table. |
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2815 This pre-allocation is useful for performance when you know in advance |
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2816 how many elements the table will have. |
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2817 Otherwise you can use the function <a href="#lua_newtable"><code>lua_newtable</code></a>. |
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2818 |
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2819 |
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2820 |
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2821 |
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2822 |
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2823 <hr><h3><a name="lua_dump"><code>lua_dump</code></a></h3><p> |
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2824 <span class="apii">[-0, +0, <em>e</em>]</span> |
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2825 <pre>int lua_dump (lua_State *L, |
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2826 lua_Writer writer, |
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2827 void *data, |
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2828 int strip);</pre> |
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2829 |
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2830 <p> |
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2831 Dumps a function as a binary chunk. |
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2832 Receives a Lua function on the top of the stack |
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2833 and produces a binary chunk that, |
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2834 if loaded again, |
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2835 results in a function equivalent to the one dumped. |
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2836 As it produces parts of the chunk, |
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2837 <a href="#lua_dump"><code>lua_dump</code></a> calls function <code>writer</code> (see <a href="#lua_Writer"><code>lua_Writer</code></a>) |
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2838 with the given <code>data</code> |
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2839 to write them. |
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2840 |
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|
2841 |
|
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diff
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|
2842 <p> |
|
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diff
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|
2843 If <code>strip</code> is true, |
|
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diff
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|
2844 the binary representation is created without debug information |
|
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diff
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|
2845 about the function. |
|
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diff
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|
2846 |
|
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diff
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|
2847 |
|
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diff
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|
2848 <p> |
|
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diff
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|
2849 The value returned is the error code returned by the last |
|
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diff
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|
2850 call to the writer; |
|
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diff
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|
2851 0 means no errors. |
|
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diff
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|
2852 |
|
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diff
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|
2853 |
|
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diff
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|
2854 <p> |
|
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|
2855 This function does not pop the Lua function from the stack. |
|
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|
2856 |
|
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diff
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|
2857 |
|
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diff
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|
2858 |
|
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Franklin Schmidt <fschmidt@gmail.com>
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diff
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|
2859 |
|
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diff
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|
2860 |
|
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|
2861 <hr><h3><a name="lua_error"><code>lua_error</code></a></h3><p> |
|
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|
2862 <span class="apii">[-1, +0, <em>v</em>]</span> |
|
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|
2863 <pre>int lua_error (lua_State *L);</pre> |
|
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|
2864 |
|
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diff
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|
2865 <p> |
|
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|
2866 Generates a Lua error, |
|
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|
2867 using the value at the top of the stack as the error object. |
|
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|
2868 This function does a long jump, |
|
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|
2869 and therefore never returns |
|
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|
2870 (see <a href="#luaL_error"><code>luaL_error</code></a>). |
|
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|
2871 |
|
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diff
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|
2872 |
|
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diff
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|
2873 |
|
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diff
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|
2874 |
|
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|
2875 |
|
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|
2876 <hr><h3><a name="lua_gc"><code>lua_gc</code></a></h3><p> |
|
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|
2877 <span class="apii">[-0, +0, <em>e</em>]</span> |
|
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|
2878 <pre>int lua_gc (lua_State *L, int what, int data);</pre> |
|
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|
2879 |
|
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diff
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|
2880 <p> |
|
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|
2881 Controls the garbage collector. |
|
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diff
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|
2882 |
|
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diff
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|
2883 |
|
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diff
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|
2884 <p> |
|
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|
2885 This function performs several tasks, |
|
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diff
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|
2886 according to the value of the parameter <code>what</code>: |
|
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|
2887 |
|
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diff
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|
2888 <ul> |
|
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diff
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|
2889 |
|
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|
2890 <li><b><code>LUA_GCSTOP</code>: </b> |
|
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|
2891 stops the garbage collector. |
|
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diff
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|
2892 </li> |
|
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diff
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|
2893 |
|
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|
2894 <li><b><code>LUA_GCRESTART</code>: </b> |
|
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|
2895 restarts the garbage collector. |
|
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diff
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|
2896 </li> |
|
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diff
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|
2897 |
|
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|
2898 <li><b><code>LUA_GCCOLLECT</code>: </b> |
|
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|
2899 performs a full garbage-collection cycle. |
|
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diff
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|
2900 </li> |
|
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diff
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|
2901 |
|
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|
2902 <li><b><code>LUA_GCCOUNT</code>: </b> |
|
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|
2903 returns the current amount of memory (in Kbytes) in use by Lua. |
|
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|
2904 </li> |
|
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diff
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|
2905 |
|
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diff
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|
2906 <li><b><code>LUA_GCCOUNTB</code>: </b> |
|
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|
2907 returns the remainder of dividing the current amount of bytes of |
|
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parents:
diff
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|
2908 memory in use by Lua by 1024. |
|
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diff
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|
2909 </li> |
|
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diff
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|
2910 |
|
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|
2911 <li><b><code>LUA_GCSTEP</code>: </b> |
|
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|
2912 performs an incremental step of garbage collection. |
|
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diff
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|
2913 </li> |
|
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diff
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|
2914 |
|
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|
2915 <li><b><code>LUA_GCSETPAUSE</code>: </b> |
|
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|
2916 sets <code>data</code> as the new value |
|
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|
2917 for the <em>pause</em> of the collector (see <a href="#2.5">§2.5</a>) |
|
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|
2918 and returns the previous value of the pause. |
|
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diff
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|
2919 </li> |
|
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diff
changeset
|
2920 |
|
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diff
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|
2921 <li><b><code>LUA_GCSETSTEPMUL</code>: </b> |
|
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|
2922 sets <code>data</code> as the new value for the <em>step multiplier</em> of |
|
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|
2923 the collector (see <a href="#2.5">§2.5</a>) |
|
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|
2924 and returns the previous value of the step multiplier. |
|
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|
2925 </li> |
|
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diff
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|
2926 |
|
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diff
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|
2927 <li><b><code>LUA_GCISRUNNING</code>: </b> |
|
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|
2928 returns a boolean that tells whether the collector is running |
|
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|
2929 (i.e., not stopped). |
|
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|
2930 </li> |
|
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diff
changeset
|
2931 |
|
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diff
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|
2932 </ul> |
|
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changeset
|
2933 |
|
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changeset
|
2934 <p> |
|
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changeset
|
2935 For more details about these options, |
|
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|
2936 see <a href="#pdf-collectgarbage"><code>collectgarbage</code></a>. |
|
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|
2937 |
|
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diff
changeset
|
2938 |
|
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diff
changeset
|
2939 |
|
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diff
changeset
|
2940 |
|
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changeset
|
2941 |
|
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|
2942 <hr><h3><a name="lua_getallocf"><code>lua_getallocf</code></a></h3><p> |
|
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|
2943 <span class="apii">[-0, +0, –]</span> |
|
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|
2944 <pre>lua_Alloc lua_getallocf (lua_State *L, void **ud);</pre> |
|
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|
2945 |
|
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changeset
|
2946 <p> |
|
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|
2947 Returns the memory-allocation function of a given state. |
|
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|
2948 If <code>ud</code> is not <code>NULL</code>, Lua stores in <code>*ud</code> the |
|
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|
2949 opaque pointer given when the memory-allocator function was set. |
|
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changeset
|
2950 |
|
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diff
changeset
|
2951 |
|
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changeset
|
2952 |
|
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changeset
|
2953 |
|
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changeset
|
2954 |
|
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|
2955 <hr><h3><a name="lua_getfield"><code>lua_getfield</code></a></h3><p> |
|
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|
2956 <span class="apii">[-0, +1, <em>e</em>]</span> |
|
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|
2957 <pre>int lua_getfield (lua_State *L, int index, const char *k);</pre> |
|
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|
2958 |
|
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|
2959 <p> |
|
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|
2960 Pushes onto the stack the value <code>t[k]</code>, |
|
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|
2961 where <code>t</code> is the value at the given index. |
|
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|
2962 As in Lua, this function may trigger a metamethod |
|
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|
2963 for the "index" event (see <a href="#2.4">§2.4</a>). |
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|
2964 |
|
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|
2965 |
|
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|
2966 <p> |
|
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|
2967 Returns the type of the pushed value. |
|
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|
2968 |
|
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|
2969 |
|
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|
2970 |
|
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changeset
|
2971 |
|
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|
2972 |
|
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|
2973 <hr><h3><a name="lua_getextraspace"><code>lua_getextraspace</code></a></h3><p> |
|
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|
2974 <span class="apii">[-0, +0, –]</span> |
|
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|
2975 <pre>void *lua_getextraspace (lua_State *L);</pre> |
|
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|
2976 |
|
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|
2977 <p> |
|
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|
2978 Returns a pointer to a raw memory area associated with the |
|
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|
2979 given Lua state. |
|
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|
2980 The application can use this area for any purpose; |
|
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|
2981 Lua does not use it for anything. |
|
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|
2982 |
|
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diff
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|
2983 |
|
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|
2984 <p> |
|
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|
2985 Each new thread has this area initialized with a copy |
|
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|
2986 of the area of the main thread. |
|
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|
2987 |
|
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|
2988 |
|
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|
2989 <p> |
|
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|
2990 By default, this area has the size of a pointer to void, |
|
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|
2991 but you can recompile Lua with a different size for this area. |
|
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|
2992 (See <code>LUA_EXTRASPACE</code> in <code>luaconf.h</code>.) |
|
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|
2993 |
|
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diff
changeset
|
2994 |
|
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diff
changeset
|
2995 |
|
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diff
changeset
|
2996 |
|
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diff
changeset
|
2997 |
|
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|
2998 <hr><h3><a name="lua_getglobal"><code>lua_getglobal</code></a></h3><p> |
|
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|
2999 <span class="apii">[-0, +1, <em>e</em>]</span> |
|
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|
3000 <pre>int lua_getglobal (lua_State *L, const char *name);</pre> |
|
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|
3001 |
|
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|
3002 <p> |
|
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diff
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|
3003 Pushes onto the stack the value of the global <code>name</code>. |
|
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|
3004 Returns the type of that value. |
|
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|
3005 |
|
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|
3006 |
|
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diff
changeset
|
3007 |
|
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|
3008 |
|
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diff
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|
3009 |
|
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|
3010 <hr><h3><a name="lua_geti"><code>lua_geti</code></a></h3><p> |
|
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|
3011 <span class="apii">[-0, +1, <em>e</em>]</span> |
|
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|
3012 <pre>int lua_geti (lua_State *L, int index, lua_Integer i);</pre> |
|
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|
3013 |
|
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|
3014 <p> |
|
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|
3015 Pushes onto the stack the value <code>t[i]</code>, |
|
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|
3016 where <code>t</code> is the value at the given index. |
|
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parents:
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|
3017 As in Lua, this function may trigger a metamethod |
|
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|
3018 for the "index" event (see <a href="#2.4">§2.4</a>). |
|
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|
3019 |
|
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|
3020 |
|
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|
3021 <p> |
|
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|
3022 Returns the type of the pushed value. |
|
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|
3023 |
|
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diff
changeset
|
3024 |
|
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changeset
|
3025 |
|
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diff
changeset
|
3026 |
|
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diff
changeset
|
3027 |
|
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|
3028 <hr><h3><a name="lua_getmetatable"><code>lua_getmetatable</code></a></h3><p> |
|
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|
3029 <span class="apii">[-0, +(0|1), –]</span> |
|
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|
3030 <pre>int lua_getmetatable (lua_State *L, int index);</pre> |
|
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|
3031 |
|
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|
3032 <p> |
|
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|
3033 If the value at the given index has a metatable, |
|
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|
3034 the function pushes that metatable onto the stack and returns 1. |
|
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|
3035 Otherwise, |
|
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|
3036 the function returns 0 and pushes nothing on the stack. |
|
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|
3037 |
|
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diff
changeset
|
3038 |
|
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diff
changeset
|
3039 |
|
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|
3040 |
|
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|
3041 |
|
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|
3042 <hr><h3><a name="lua_gettable"><code>lua_gettable</code></a></h3><p> |
|
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|
3043 <span class="apii">[-1, +1, <em>e</em>]</span> |
|
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|
3044 <pre>int lua_gettable (lua_State *L, int index);</pre> |
|
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|
3045 |
|
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|
3046 <p> |
|
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|
3047 Pushes onto the stack the value <code>t[k]</code>, |
|
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|
3048 where <code>t</code> is the value at the given index |
|
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|
3049 and <code>k</code> is the value at the top of the stack. |
|
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|
3050 |
|
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diff
changeset
|
3051 |
|
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|
3052 <p> |
|
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|
3053 This function pops the key from the stack, |
|
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|
3054 pushing the resulting value in its place. |
|
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|
3055 As in Lua, this function may trigger a metamethod |
|
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|
3056 for the "index" event (see <a href="#2.4">§2.4</a>). |
|
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|
3057 |
|
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|
3058 |
|
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|
3059 <p> |
|
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|
3060 Returns the type of the pushed value. |
|
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|
3061 |
|
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diff
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|
3062 |
|
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|
3063 |
|
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|
3064 |
|
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|
3065 |
|
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|
3066 <hr><h3><a name="lua_gettop"><code>lua_gettop</code></a></h3><p> |
|
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|
3067 <span class="apii">[-0, +0, –]</span> |
|
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|
3068 <pre>int lua_gettop (lua_State *L);</pre> |
|
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|
3069 |
|
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|
3070 <p> |
|
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|
3071 Returns the index of the top element in the stack. |
|
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changeset
|
3072 Because indices start at 1, |
|
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|
3073 this result is equal to the number of elements in the stack; |
|
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|
3074 in particular, 0 means an empty stack. |
|
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changeset
|
3075 |
|
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|
3076 |
|
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|
3077 |
|
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|
3078 |
|
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diff
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|
3079 |
|
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|
3080 <hr><h3><a name="lua_getuservalue"><code>lua_getuservalue</code></a></h3><p> |
|
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3081 <span class="apii">[-0, +1, –]</span> |
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|
3082 <pre>int lua_getuservalue (lua_State *L, int index);</pre> |
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|
3083 |
|
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|
3084 <p> |
|
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|
3085 Pushes onto the stack the Lua value associated with the userdata |
|
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3086 at the given index. |
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|
3087 |
|
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|
3088 |
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|
3089 <p> |
|
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|
3090 Returns the type of the pushed value. |
|
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|
3091 |
|
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|
3092 |
|
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|
3093 |
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|
3094 |
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|
3095 |
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|
3096 <hr><h3><a name="lua_insert"><code>lua_insert</code></a></h3><p> |
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|
3097 <span class="apii">[-1, +1, –]</span> |
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|
3098 <pre>void lua_insert (lua_State *L, int index);</pre> |
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|
3099 |
|
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|
3100 <p> |
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|
3101 Moves the top element into the given valid index, |
|
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3102 shifting up the elements above this index to open space. |
|
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3103 This function cannot be called with a pseudo-index, |
|
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3104 because a pseudo-index is not an actual stack position. |
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|
3105 |
|
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|
3106 |
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|
3107 |
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|
3108 |
|
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|
3109 |
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|
3110 <hr><h3><a name="lua_Integer"><code>lua_Integer</code></a></h3> |
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3111 <pre>typedef ... lua_Integer;</pre> |
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3112 |
|
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|
3113 <p> |
|
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|
3114 The type of integers in Lua. |
|
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|
3115 |
|
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|
3116 |
|
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|
3117 <p> |
|
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|
3118 By default this type is <code>long long</code>, |
|
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|
3119 (usually a 64-bit two-complement integer), |
|
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|
3120 but that can be changed to <code>long</code> or <code>int</code> |
|
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3121 (usually a 32-bit two-complement integer). |
|
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|
3122 (See <code>LUA_INT</code> in <code>luaconf.h</code>.) |
|
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|
3123 |
|
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|
3124 |
|
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|
3125 <p> |
|
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|
3126 Lua also defines the constants |
|
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3127 <a name="pdf-LUA_MININTEGER"><code>LUA_MININTEGER</code></a> and <a name="pdf-LUA_MAXINTEGER"><code>LUA_MAXINTEGER</code></a>, |
|
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|
3128 with the minimum and the maximum values that fit in this type. |
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|
3129 |
|
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diff
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|
3130 |
|
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Franklin Schmidt <fschmidt@gmail.com>
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|
3131 |
|
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|
3132 |
|
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|
3133 |
|
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|
3134 <hr><h3><a name="lua_isboolean"><code>lua_isboolean</code></a></h3><p> |
|
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|
3135 <span class="apii">[-0, +0, –]</span> |
|
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|
3136 <pre>int lua_isboolean (lua_State *L, int index);</pre> |
|
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|
3137 |
|
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|
3138 <p> |
|
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|
3139 Returns 1 if the value at the given index is a boolean, |
|
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|
3140 and 0 otherwise. |
|
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|
3141 |
|
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Franklin Schmidt <fschmidt@gmail.com>
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diff
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|
3142 |
|
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Franklin Schmidt <fschmidt@gmail.com>
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diff
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|
3143 |
|
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Franklin Schmidt <fschmidt@gmail.com>
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|
3144 |
|
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Franklin Schmidt <fschmidt@gmail.com>
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diff
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|
3145 |
|
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|
3146 <hr><h3><a name="lua_iscfunction"><code>lua_iscfunction</code></a></h3><p> |
|
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|
3147 <span class="apii">[-0, +0, –]</span> |
|
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|
3148 <pre>int lua_iscfunction (lua_State *L, int index);</pre> |
|
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|
3149 |
|
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|
3150 <p> |
|
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|
3151 Returns 1 if the value at the given index is a C function, |
|
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parents:
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|
3152 and 0 otherwise. |
|
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diff
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|
3153 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
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|
3154 |
|
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Franklin Schmidt <fschmidt@gmail.com>
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diff
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|
3155 |
|
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Franklin Schmidt <fschmidt@gmail.com>
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|
3156 |
|
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Franklin Schmidt <fschmidt@gmail.com>
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diff
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|
3157 |
|
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|
3158 <hr><h3><a name="lua_isfunction"><code>lua_isfunction</code></a></h3><p> |
|
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|
3159 <span class="apii">[-0, +0, –]</span> |
|
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|
3160 <pre>int lua_isfunction (lua_State *L, int index);</pre> |
|
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|
3161 |
|
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|
3162 <p> |
|
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|
3163 Returns 1 if the value at the given index is a function |
|
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|
3164 (either C or Lua), and 0 otherwise. |
|
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|
3165 |
|
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|
3166 |
|
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|
3167 |
|
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|
3168 |
|
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|
3169 |
|
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|
3170 <hr><h3><a name="lua_isinteger"><code>lua_isinteger</code></a></h3><p> |
|
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3171 <span class="apii">[-0, +0, –]</span> |
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|
3172 <pre>int lua_isinteger (lua_State *L, int index);</pre> |
|
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|
3173 |
|
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3174 <p> |
|
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|
3175 Returns 1 if the value at the given index is an integer |
|
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|
3176 (that is, the value is a number and is represented as an integer), |
|
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|
3177 and 0 otherwise. |
|
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changeset
|
3178 |
|
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changeset
|
3179 |
|
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changeset
|
3180 |
|
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changeset
|
3181 |
|
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|
3182 |
|
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|
3183 <hr><h3><a name="lua_islightuserdata"><code>lua_islightuserdata</code></a></h3><p> |
|
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|
3184 <span class="apii">[-0, +0, –]</span> |
|
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|
3185 <pre>int lua_islightuserdata (lua_State *L, int index);</pre> |
|
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|
3186 |
|
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3187 <p> |
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|
3188 Returns 1 if the value at the given index is a light userdata, |
|
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|
3189 and 0 otherwise. |
|
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parents:
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changeset
|
3190 |
|
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changeset
|
3191 |
|
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parents:
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changeset
|
3192 |
|
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changeset
|
3193 |
|
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|
3194 |
|
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|
3195 <hr><h3><a name="lua_isnil"><code>lua_isnil</code></a></h3><p> |
|
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changeset
|
3196 <span class="apii">[-0, +0, –]</span> |
|
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add manual.html as copy of Lua 5.3 Reference Manual
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parents:
diff
changeset
|
3197 <pre>int lua_isnil (lua_State *L, int index);</pre> |
|
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add manual.html as copy of Lua 5.3 Reference Manual
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parents:
diff
changeset
|
3198 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3199 <p> |
|
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add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3200 Returns 1 if the value at the given index is <b>nil</b>, |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3201 and 0 otherwise. |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3202 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3203 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3204 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3205 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3206 |
|
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add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3207 <hr><h3><a name="lua_isnone"><code>lua_isnone</code></a></h3><p> |
|
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add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3208 <span class="apii">[-0, +0, –]</span> |
|
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add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3209 <pre>int lua_isnone (lua_State *L, int index);</pre> |
|
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add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3210 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3211 <p> |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3212 Returns 1 if the given index is not valid, |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3213 and 0 otherwise. |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3214 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3215 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3216 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3217 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3218 |
|
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add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
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|
3219 <hr><h3><a name="lua_isnoneornil"><code>lua_isnoneornil</code></a></h3><p> |
|
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add manual.html as copy of Lua 5.3 Reference Manual
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parents:
diff
changeset
|
3220 <span class="apii">[-0, +0, –]</span> |
|
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add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3221 <pre>int lua_isnoneornil (lua_State *L, int index);</pre> |
|
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add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3222 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3223 <p> |
|
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add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3224 Returns 1 if the given index is not valid |
|
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add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3225 or if the value at this index is <b>nil</b>, |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3226 and 0 otherwise. |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3227 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3228 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3229 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3230 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3231 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3232 <hr><h3><a name="lua_isnumber"><code>lua_isnumber</code></a></h3><p> |
|
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add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3233 <span class="apii">[-0, +0, –]</span> |
|
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add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3234 <pre>int lua_isnumber (lua_State *L, int index);</pre> |
|
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add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3235 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3236 <p> |
|
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add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3237 Returns 1 if the value at the given index is a number |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3238 or a string convertible to a number, |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3239 and 0 otherwise. |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3240 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3241 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3242 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3243 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3244 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3245 <hr><h3><a name="lua_isstring"><code>lua_isstring</code></a></h3><p> |
|
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add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3246 <span class="apii">[-0, +0, –]</span> |
|
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add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3247 <pre>int lua_isstring (lua_State *L, int index);</pre> |
|
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add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3248 |
|
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add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3249 <p> |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3250 Returns 1 if the value at the given index is a string |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3251 or a number (which is always convertible to a string), |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3252 and 0 otherwise. |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3253 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3254 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3255 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3256 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3257 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3258 <hr><h3><a name="lua_istable"><code>lua_istable</code></a></h3><p> |
|
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add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3259 <span class="apii">[-0, +0, –]</span> |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3260 <pre>int lua_istable (lua_State *L, int index);</pre> |
|
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add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3261 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3262 <p> |
|
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add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3263 Returns 1 if the value at the given index is a table, |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3264 and 0 otherwise. |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3265 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3266 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3267 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3268 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3269 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3270 <hr><h3><a name="lua_isthread"><code>lua_isthread</code></a></h3><p> |
|
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add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3271 <span class="apii">[-0, +0, –]</span> |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3272 <pre>int lua_isthread (lua_State *L, int index);</pre> |
|
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add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3273 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3274 <p> |
|
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add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3275 Returns 1 if the value at the given index is a thread, |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3276 and 0 otherwise. |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3277 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3278 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3279 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3280 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3281 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3282 <hr><h3><a name="lua_isuserdata"><code>lua_isuserdata</code></a></h3><p> |
|
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add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3283 <span class="apii">[-0, +0, –]</span> |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3284 <pre>int lua_isuserdata (lua_State *L, int index);</pre> |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3285 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3286 <p> |
|
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add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3287 Returns 1 if the value at the given index is a userdata |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3288 (either full or light), and 0 otherwise. |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3289 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3290 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3291 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3292 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3293 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3294 <hr><h3><a name="lua_isyieldable"><code>lua_isyieldable</code></a></h3><p> |
|
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add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3295 <span class="apii">[-0, +0, –]</span> |
|
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add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3296 <pre>int lua_isyieldable (lua_State *L);</pre> |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3297 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3298 <p> |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3299 Returns 1 if the given coroutine can yield, |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3300 and 0 otherwise. |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3301 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3302 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3303 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3304 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3305 |
|
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add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3306 <hr><h3><a name="lua_KContext"><code>lua_KContext</code></a></h3> |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3307 <pre>typedef ... lua_KContext;</pre> |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3308 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3309 <p> |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3310 The type for continuation-function contexts. |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3311 It must be a numerical type. |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3312 This type is defined as <code>intptr_t</code> |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3313 when <code>intptr_t</code> is available, |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3314 so that it can store pointers too. |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3315 Otherwise, it is defined as <code>ptrdiff_t</code>. |
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3316 |
|
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|
3317 |
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|
3318 |
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|
3319 |
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3320 |
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3321 <hr><h3><a name="lua_KFunction"><code>lua_KFunction</code></a></h3> |
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3322 <pre>typedef int (*lua_KFunction) (lua_State *L, int status, lua_KContext ctx);</pre> |
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3323 |
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3324 <p> |
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|
3325 Type for continuation functions (see <a href="#4.7">§4.7</a>). |
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3326 |
|
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|
3327 |
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|
3328 |
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|
3329 |
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3330 |
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|
3331 <hr><h3><a name="lua_len"><code>lua_len</code></a></h3><p> |
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3332 <span class="apii">[-0, +1, <em>e</em>]</span> |
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3333 <pre>void lua_len (lua_State *L, int index);</pre> |
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3334 |
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|
3335 <p> |
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|
3336 Returns the length of the value at the given index. |
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3337 It is equivalent to the '<code>#</code>' operator in Lua (see <a href="#3.4.7">§3.4.7</a>) and |
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|
3338 may trigger a metamethod for the "length" event (see <a href="#2.4">§2.4</a>). |
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3339 The result is pushed on the stack. |
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3340 |
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3341 |
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3342 |
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3343 |
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3344 |
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3345 <hr><h3><a name="lua_load"><code>lua_load</code></a></h3><p> |
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3346 <span class="apii">[-0, +1, –]</span> |
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|
3347 <pre>int lua_load (lua_State *L, |
|
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3348 lua_Reader reader, |
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3349 void *data, |
|
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3350 const char *chunkname, |
|
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|
3351 const char *mode);</pre> |
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3352 |
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3353 <p> |
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3354 Loads a Lua chunk without running it. |
|
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3355 If there are no errors, |
|
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|
3356 <code>lua_load</code> pushes the compiled chunk as a Lua |
|
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3357 function on top of the stack. |
|
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|
3358 Otherwise, it pushes an error message. |
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3359 |
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3360 |
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3361 <p> |
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3362 The return values of <code>lua_load</code> are: |
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3363 |
|
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|
3364 <ul> |
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3365 |
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|
3366 <li><b><a href="#pdf-LUA_OK"><code>LUA_OK</code></a>: </b> no errors;</li> |
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3367 |
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|
3368 <li><b><a name="pdf-LUA_ERRSYNTAX"><code>LUA_ERRSYNTAX</code></a>: </b> |
|
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|
3369 syntax error during precompilation;</li> |
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3370 |
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|
3371 <li><b><a href="#pdf-LUA_ERRMEM"><code>LUA_ERRMEM</code></a>: </b> |
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|
3372 memory allocation error;</li> |
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3373 |
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|
3374 <li><b><a href="#pdf-LUA_ERRGCMM"><code>LUA_ERRGCMM</code></a>: </b> |
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|
3375 error while running a <code>__gc</code> metamethod. |
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3376 (This error has no relation with the chunk being loaded. |
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|
3377 It is generated by the garbage collector.) |
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3378 </li> |
|
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|
3379 |
|
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|
3380 </ul> |
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3381 |
|
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|
3382 <p> |
|
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|
3383 The <code>lua_load</code> function uses a user-supplied <code>reader</code> function |
|
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|
3384 to read the chunk (see <a href="#lua_Reader"><code>lua_Reader</code></a>). |
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|
3385 The <code>data</code> argument is an opaque value passed to the reader function. |
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|
3386 |
|
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|
3387 |
|
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|
3388 <p> |
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|
3389 The <code>chunkname</code> argument gives a name to the chunk, |
|
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|
3390 which is used for error messages and in debug information (see <a href="#4.9">§4.9</a>). |
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|
3391 |
|
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|
3392 |
|
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|
3393 <p> |
|
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|
3394 <code>lua_load</code> automatically detects whether the chunk is text or binary |
|
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|
3395 and loads it accordingly (see program <code>luac</code>). |
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|
3396 The string <code>mode</code> works as in function <a href="#pdf-load"><code>load</code></a>, |
|
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|
3397 with the addition that |
|
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|
3398 a <code>NULL</code> value is equivalent to the string "<code>bt</code>". |
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|
3399 |
|
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|
3400 |
|
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|
3401 <p> |
|
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|
3402 <code>lua_load</code> uses the stack internally, |
|
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3403 so the reader function must always leave the stack |
|
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3404 unmodified when returning. |
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|
3405 |
|
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|
3406 |
|
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3407 <p> |
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|
3408 If the resulting function has upvalues, |
|
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3409 its first upvalue is set to the value of the global environment |
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3410 stored at index <code>LUA_RIDX_GLOBALS</code> in the registry (see <a href="#4.5">§4.5</a>). |
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3411 When loading main chunks, |
|
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|
3412 this upvalue will be the <code>_ENV</code> variable (see <a href="#2.2">§2.2</a>). |
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3413 Other upvalues are initialized with <b>nil</b>. |
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3414 |
|
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|
3415 |
|
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|
3416 |
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|
3417 |
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3418 |
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|
3419 <hr><h3><a name="lua_newstate"><code>lua_newstate</code></a></h3><p> |
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3420 <span class="apii">[-0, +0, –]</span> |
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|
3421 <pre>lua_State *lua_newstate (lua_Alloc f, void *ud);</pre> |
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3422 |
|
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3423 <p> |
|
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|
3424 Creates a new thread running in a new, independent state. |
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3425 Returns <code>NULL</code> if it cannot create the thread or the state |
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3426 (due to lack of memory). |
|
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3427 The argument <code>f</code> is the allocator function; |
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3428 Lua does all memory allocation for this state through this function. |
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|
3429 The second argument, <code>ud</code>, is an opaque pointer that Lua |
|
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3430 passes to the allocator in every call. |
|
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|
3431 |
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|
3432 |
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|
3433 |
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|
3434 |
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|
3435 |
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|
3436 <hr><h3><a name="lua_newtable"><code>lua_newtable</code></a></h3><p> |
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3437 <span class="apii">[-0, +1, <em>e</em>]</span> |
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|
3438 <pre>void lua_newtable (lua_State *L);</pre> |
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3439 |
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|
3440 <p> |
|
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|
3441 Creates a new empty table and pushes it onto the stack. |
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|
3442 It is equivalent to <code>lua_createtable(L, 0, 0)</code>. |
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3443 |
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|
3444 |
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3445 |
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3446 |
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3447 |
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3448 <hr><h3><a name="lua_newthread"><code>lua_newthread</code></a></h3><p> |
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|
3449 <span class="apii">[-0, +1, <em>e</em>]</span> |
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|
3450 <pre>lua_State *lua_newthread (lua_State *L);</pre> |
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3451 |
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|
3452 <p> |
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|
3453 Creates a new thread, pushes it on the stack, |
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|
3454 and returns a pointer to a <a href="#lua_State"><code>lua_State</code></a> that represents this new thread. |
|
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3455 The new thread returned by this function shares with the original thread |
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|
3456 its global environment, |
|
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|
3457 but has an independent execution stack. |
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3458 |
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|
3459 |
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|
3460 <p> |
|
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|
3461 There is no explicit function to close or to destroy a thread. |
|
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|
3462 Threads are subject to garbage collection, |
|
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3463 like any Lua object. |
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|
3464 |
|
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|
3465 |
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|
3466 |
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|
3467 |
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3468 |
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|
3469 <hr><h3><a name="lua_newuserdata"><code>lua_newuserdata</code></a></h3><p> |
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|
3470 <span class="apii">[-0, +1, <em>e</em>]</span> |
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|
3471 <pre>void *lua_newuserdata (lua_State *L, size_t size);</pre> |
|
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|
3472 |
|
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|
3473 <p> |
|
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|
3474 This function allocates a new block of memory with the given size, |
|
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|
3475 pushes onto the stack a new full userdata with the block address, |
|
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|
3476 and returns this address. |
|
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|
3477 The host program can freely use this memory. |
|
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|
3478 |
|
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|
3479 |
|
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|
3480 |
|
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|
3481 |
|
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|
3482 |
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|
3483 <hr><h3><a name="lua_next"><code>lua_next</code></a></h3><p> |
|
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|
3484 <span class="apii">[-1, +(2|0), <em>e</em>]</span> |
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|
3485 <pre>int lua_next (lua_State *L, int index);</pre> |
|
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3486 |
|
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|
3487 <p> |
|
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|
3488 Pops a key from the stack, |
|
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|
3489 and pushes a key–value pair from the table at the given index |
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|
3490 (the "next" pair after the given key). |
|
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|
3491 If there are no more elements in the table, |
|
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|
3492 then <a href="#lua_next"><code>lua_next</code></a> returns 0 (and pushes nothing). |
|
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|
3493 |
|
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|
3494 |
|
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|
3495 <p> |
|
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|
3496 A typical traversal looks like this: |
|
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|
3497 |
|
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|
3498 <pre> |
|
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|
3499 /* table is in the stack at index 't' */ |
|
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|
3500 lua_pushnil(L); /* first key */ |
|
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|
3501 while (lua_next(L, t) != 0) { |
|
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|
3502 /* uses 'key' (at index -2) and 'value' (at index -1) */ |
|
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|
3503 printf("%s - %s\n", |
|
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|
3504 lua_typename(L, lua_type(L, -2)), |
|
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|
3505 lua_typename(L, lua_type(L, -1))); |
|
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|
3506 /* removes 'value'; keeps 'key' for next iteration */ |
|
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|
3507 lua_pop(L, 1); |
|
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|
3508 } |
|
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|
3509 </pre> |
|
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|
3510 |
|
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|
3511 <p> |
|
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|
3512 While traversing a table, |
|
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|
3513 do not call <a href="#lua_tolstring"><code>lua_tolstring</code></a> directly on a key, |
|
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|
3514 unless you know that the key is actually a string. |
|
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|
3515 Recall that <a href="#lua_tolstring"><code>lua_tolstring</code></a> may change |
|
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|
3516 the value at the given index; |
|
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|
3517 this confuses the next call to <a href="#lua_next"><code>lua_next</code></a>. |
|
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|
3518 |
|
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|
3519 |
|
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|
3520 <p> |
|
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|
3521 See function <a href="#pdf-next"><code>next</code></a> for the caveats of modifying |
|
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|
3522 the table during its traversal. |
|
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|
3523 |
|
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|
3524 |
|
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|
3525 |
|
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|
3526 |
|
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|
3527 |
|
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|
3528 <hr><h3><a name="lua_Number"><code>lua_Number</code></a></h3> |
|
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|
3529 <pre>typedef double lua_Number;</pre> |
|
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|
3530 |
|
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|
3531 <p> |
|
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|
3532 The type of floats in Lua. |
|
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3533 |
|
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|
3534 |
|
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|
3535 <p> |
|
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|
3536 By default this type is double, |
|
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3537 but that can be changed to a single float. |
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|
3538 (See <code>LUA_REAL</code> in <code>luaconf.h</code>.) |
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|
3539 |
|
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|
3540 |
|
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|
3541 |
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|
3542 |
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|
3543 |
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|
3544 <hr><h3><a name="lua_numbertointeger"><code>lua_numbertointeger</code></a></h3> |
|
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|
3545 <pre>int lua_numbertointeger (lua_Number n, lua_Integer *p);</pre> |
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3546 |
|
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|
3547 <p> |
|
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|
3548 Converts a Lua float to a Lua integer. |
|
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|
3549 This macro assumes that <code>n</code> has an integral value. |
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|
3550 If that value is within the range of Lua integers, |
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|
3551 it is converted to an integer and assigned to <code>*p</code>. |
|
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|
3552 The macro results in a boolean indicating whether the |
|
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|
3553 conversion was successful. |
|
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|
3554 (Note that this range test can be tricky to do |
|
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|
3555 correctly without this macro, |
|
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|
3556 due to roundings.) |
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|
3557 |
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|
3558 |
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|
3559 <p> |
|
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|
3560 This macro may evaluate its arguments more than once. |
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3561 |
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|
3562 |
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|
3563 |
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|
3564 |
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|
3565 |
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|
3566 <hr><h3><a name="lua_pcall"><code>lua_pcall</code></a></h3><p> |
|
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|
3567 <span class="apii">[-(nargs + 1), +(nresults|1), –]</span> |
|
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|
3568 <pre>int lua_pcall (lua_State *L, int nargs, int nresults, int msgh);</pre> |
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3569 |
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|
3570 <p> |
|
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|
3571 Calls a function in protected mode. |
|
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|
3572 |
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|
3573 |
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|
3574 <p> |
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|
3575 Both <code>nargs</code> and <code>nresults</code> have the same meaning as |
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|
3576 in <a href="#lua_call"><code>lua_call</code></a>. |
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|
3577 If there are no errors during the call, |
|
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|
3578 <a href="#lua_pcall"><code>lua_pcall</code></a> behaves exactly like <a href="#lua_call"><code>lua_call</code></a>. |
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|
3579 However, if there is any error, |
|
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|
3580 <a href="#lua_pcall"><code>lua_pcall</code></a> catches it, |
|
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|
3581 pushes a single value on the stack (the error message), |
|
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|
3582 and returns an error code. |
|
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|
3583 Like <a href="#lua_call"><code>lua_call</code></a>, |
|
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|
3584 <a href="#lua_pcall"><code>lua_pcall</code></a> always removes the function |
|
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|
3585 and its arguments from the stack. |
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|
3586 |
|
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|
3587 |
|
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|
3588 <p> |
|
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|
3589 If <code>msgh</code> is 0, |
|
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|
3590 then the error message returned on the stack |
|
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|
3591 is exactly the original error message. |
|
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|
3592 Otherwise, <code>msgh</code> is the stack index of a |
|
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|
3593 <em>message handler</em>. |
|
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|
3594 (In the current implementation, this index cannot be a pseudo-index.) |
|
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|
3595 In case of runtime errors, |
|
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|
3596 this function will be called with the error message |
|
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|
3597 and its return value will be the message |
|
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|
3598 returned on the stack by <a href="#lua_pcall"><code>lua_pcall</code></a>. |
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|
3599 |
|
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|
3600 |
|
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|
3601 <p> |
|
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|
3602 Typically, the message handler is used to add more debug |
|
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|
3603 information to the error message, such as a stack traceback. |
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|
3604 Such information cannot be gathered after the return of <a href="#lua_pcall"><code>lua_pcall</code></a>, |
|
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|
3605 since by then the stack has unwound. |
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|
3606 |
|
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|
3607 |
|
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|
3608 <p> |
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|
3609 The <a href="#lua_pcall"><code>lua_pcall</code></a> function returns one of the following constants |
|
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|
3610 (defined in <code>lua.h</code>): |
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|
3611 |
|
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|
3612 <ul> |
|
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|
3613 |
|
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|
3614 <li><b><a name="pdf-LUA_OK"><code>LUA_OK</code></a> (0): </b> |
|
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|
3615 success.</li> |
|
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|
3616 |
|
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|
3617 <li><b><a name="pdf-LUA_ERRRUN"><code>LUA_ERRRUN</code></a>: </b> |
|
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|
3618 a runtime error. |
|
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|
3619 </li> |
|
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|
3620 |
|
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|
3621 <li><b><a name="pdf-LUA_ERRMEM"><code>LUA_ERRMEM</code></a>: </b> |
|
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|
3622 memory allocation error. |
|
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|
3623 For such errors, Lua does not call the message handler. |
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|
3624 </li> |
|
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|
3625 |
|
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|
3626 <li><b><a name="pdf-LUA_ERRERR"><code>LUA_ERRERR</code></a>: </b> |
|
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|
3627 error while running the message handler. |
|
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|
3628 </li> |
|
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|
3629 |
|
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|
3630 <li><b><a name="pdf-LUA_ERRGCMM"><code>LUA_ERRGCMM</code></a>: </b> |
|
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|
3631 error while running a <code>__gc</code> metamethod. |
|
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|
3632 (This error typically has no relation with the function being called.) |
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|
3633 </li> |
|
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|
3634 |
|
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|
3635 </ul> |
|
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|
3636 |
|
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|
3637 |
|
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|
3638 |
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|
3639 |
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|
3640 <hr><h3><a name="lua_pcallk"><code>lua_pcallk</code></a></h3><p> |
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|
3641 <span class="apii">[-(nargs + 1), +(nresults|1), –]</span> |
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|
3642 <pre>int lua_pcallk (lua_State *L, |
|
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3643 int nargs, |
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|
3644 int nresults, |
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3645 int msgh, |
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|
3646 lua_KContext ctx, |
|
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|
3647 lua_KFunction k);</pre> |
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3648 |
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|
3649 <p> |
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|
3650 This function behaves exactly like <a href="#lua_pcall"><code>lua_pcall</code></a>, |
|
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|
3651 but allows the called function to yield (see <a href="#4.7">§4.7</a>). |
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|
3652 |
|
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|
3653 |
|
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|
3654 |
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|
3655 |
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|
3656 |
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|
3657 <hr><h3><a name="lua_pop"><code>lua_pop</code></a></h3><p> |
|
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3658 <span class="apii">[-n, +0, –]</span> |
|
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|
3659 <pre>void lua_pop (lua_State *L, int n);</pre> |
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|
3660 |
|
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|
3661 <p> |
|
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|
3662 Pops <code>n</code> elements from the stack. |
|
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|
3663 |
|
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|
3664 |
|
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|
3665 |
|
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diff
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|
3666 |
|
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diff
changeset
|
3667 |
|
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|
3668 <hr><h3><a name="lua_pushboolean"><code>lua_pushboolean</code></a></h3><p> |
|
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|
3669 <span class="apii">[-0, +1, –]</span> |
|
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|
3670 <pre>void lua_pushboolean (lua_State *L, int b);</pre> |
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|
3671 |
|
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|
3672 <p> |
|
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|
3673 Pushes a boolean value with value <code>b</code> onto the stack. |
|
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|
3674 |
|
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|
3675 |
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|
3676 |
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diff
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|
3677 |
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diff
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|
3678 |
|
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|
3679 <hr><h3><a name="lua_pushcclosure"><code>lua_pushcclosure</code></a></h3><p> |
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|
3680 <span class="apii">[-n, +1, <em>e</em>]</span> |
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|
3681 <pre>void lua_pushcclosure (lua_State *L, lua_CFunction fn, int n);</pre> |
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3682 |
|
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|
3683 <p> |
|
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|
3684 Pushes a new C closure onto the stack. |
|
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|
3685 |
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|
3686 |
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|
3687 <p> |
|
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|
3688 When a C function is created, |
|
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3689 it is possible to associate some values with it, |
|
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|
3690 thus creating a C closure (see <a href="#4.4">§4.4</a>); |
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3691 these values are then accessible to the function whenever it is called. |
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|
3692 To associate values with a C function, |
|
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|
3693 first these values must be pushed onto the stack |
|
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|
3694 (when there are multiple values, the first value is pushed first). |
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|
3695 Then <a href="#lua_pushcclosure"><code>lua_pushcclosure</code></a> |
|
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|
3696 is called to create and push the C function onto the stack, |
|
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|
3697 with the argument <code>n</code> telling how many values will be |
|
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|
3698 associated with the function. |
|
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|
3699 <a href="#lua_pushcclosure"><code>lua_pushcclosure</code></a> also pops these values from the stack. |
|
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|
3700 |
|
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|
3701 |
|
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|
3702 <p> |
|
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|
3703 The maximum value for <code>n</code> is 255. |
|
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|
3704 |
|
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|
3705 |
|
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|
3706 <p> |
|
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|
3707 When <code>n</code> is zero, |
|
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|
3708 this function creates a <em>light C function</em>, |
|
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|
3709 which is just a pointer to the C function. |
|
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|
3710 In that case, it never raises a memory error. |
|
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|
3711 |
|
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|
3712 |
|
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|
3713 |
|
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|
3714 |
|
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|
3715 |
|
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|
3716 <hr><h3><a name="lua_pushcfunction"><code>lua_pushcfunction</code></a></h3><p> |
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|
3717 <span class="apii">[-0, +1, –]</span> |
|
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|
3718 <pre>void lua_pushcfunction (lua_State *L, lua_CFunction f);</pre> |
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|
3719 |
|
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|
3720 <p> |
|
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|
3721 Pushes a C function onto the stack. |
|
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|
3722 This function receives a pointer to a C function |
|
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|
3723 and pushes onto the stack a Lua value of type <code>function</code> that, |
|
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|
3724 when called, invokes the corresponding C function. |
|
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|
3725 |
|
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diff
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|
3726 |
|
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|
3727 <p> |
|
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|
3728 Any function to be registered in Lua must |
|
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|
3729 follow the correct protocol to receive its parameters |
|
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|
3730 and return its results (see <a href="#lua_CFunction"><code>lua_CFunction</code></a>). |
|
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|
3731 |
|
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|
3732 |
|
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|
3733 <p> |
|
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|
3734 <code>lua_pushcfunction</code> is defined as a macro: |
|
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|
3735 |
|
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|
3736 <pre> |
|
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|
3737 #define lua_pushcfunction(L,f) lua_pushcclosure(L,f,0) |
|
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|
3738 </pre><p> |
|
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|
3739 Note that <code>f</code> is used twice. |
|
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|
3740 |
|
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diff
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|
3741 |
|
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Franklin Schmidt <fschmidt@gmail.com>
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|
3742 |
|
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Franklin Schmidt <fschmidt@gmail.com>
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diff
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|
3743 |
|
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|
3744 |
|
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|
3745 <hr><h3><a name="lua_pushfstring"><code>lua_pushfstring</code></a></h3><p> |
|
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|
3746 <span class="apii">[-0, +1, <em>e</em>]</span> |
|
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|
3747 <pre>const char *lua_pushfstring (lua_State *L, const char *fmt, ...);</pre> |
|
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|
3748 |
|
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|
3749 <p> |
|
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|
3750 Pushes onto the stack a formatted string |
|
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|
3751 and returns a pointer to this string. |
|
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|
3752 It is similar to the ISO C function <code>sprintf</code>, |
|
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|
3753 but has some important differences: |
|
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|
3754 |
|
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|
3755 <ul> |
|
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|
3756 |
|
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|
3757 <li> |
|
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|
3758 You do not have to allocate space for the result: |
|
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|
3759 the result is a Lua string and Lua takes care of memory allocation |
|
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|
3760 (and deallocation, through garbage collection). |
|
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|
3761 </li> |
|
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|
3762 |
|
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|
3763 <li> |
|
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|
3764 The conversion specifiers are quite restricted. |
|
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|
3765 There are no flags, widths, or precisions. |
|
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|
3766 The conversion specifiers can only be |
|
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|
3767 '<code>%%</code>' (inserts the character '<code>%</code>'), |
|
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|
3768 '<code>%s</code>' (inserts a zero-terminated string, with no size restrictions), |
|
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|
3769 '<code>%f</code>' (inserts a <a href="#lua_Number"><code>lua_Number</code></a>), |
|
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|
3770 '<code>%L</code>' (inserts a <a href="#lua_Integer"><code>lua_Integer</code></a>), |
|
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|
3771 '<code>%p</code>' (inserts a pointer as a hexadecimal numeral), |
|
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|
3772 '<code>%d</code>' (inserts an <code>int</code>), |
|
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|
3773 '<code>%c</code>' (inserts an <code>int</code> as a one-byte character), and |
|
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|
3774 '<code>%U</code>' (inserts a <code>long int</code> as a UTF-8 byte sequence). |
|
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|
3775 </li> |
|
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|
3776 |
|
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|
3777 </ul> |
|
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|
3778 |
|
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changeset
|
3779 |
|
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changeset
|
3780 |
|
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diff
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|
3781 |
|
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add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
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|
3782 <hr><h3><a name="lua_pushglobaltable"><code>lua_pushglobaltable</code></a></h3><p> |
|
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add manual.html as copy of Lua 5.3 Reference Manual
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parents:
diff
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|
3783 <span class="apii">[-0, +1, –]</span> |
|
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add manual.html as copy of Lua 5.3 Reference Manual
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parents:
diff
changeset
|
3784 <pre>void lua_pushglobaltable (lua_State *L);</pre> |
|
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parents:
diff
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|
3785 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
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|
3786 <p> |
|
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add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3787 Pushes the global environment onto the stack. |
|
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parents:
diff
changeset
|
3788 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3789 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3790 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3791 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3792 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
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|
3793 <hr><h3><a name="lua_pushinteger"><code>lua_pushinteger</code></a></h3><p> |
|
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add manual.html as copy of Lua 5.3 Reference Manual
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parents:
diff
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|
3794 <span class="apii">[-0, +1, –]</span> |
|
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add manual.html as copy of Lua 5.3 Reference Manual
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parents:
diff
changeset
|
3795 <pre>void lua_pushinteger (lua_State *L, lua_Integer n);</pre> |
|
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diff
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|
3796 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
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|
3797 <p> |
|
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parents:
diff
changeset
|
3798 Pushes an integer with value <code>n</code> onto the stack. |
|
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parents:
diff
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|
3799 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3800 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3801 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3802 |
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3803 |
|
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parents:
diff
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|
3804 <hr><h3><a name="lua_pushlightuserdata"><code>lua_pushlightuserdata</code></a></h3><p> |
|
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diff
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|
3805 <span class="apii">[-0, +1, –]</span> |
|
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parents:
diff
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|
3806 <pre>void lua_pushlightuserdata (lua_State *L, void *p);</pre> |
|
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parents:
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|
3807 |
|
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Franklin Schmidt <fschmidt@gmail.com>
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diff
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|
3808 <p> |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3809 Pushes a light userdata onto the stack. |
|
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parents:
diff
changeset
|
3810 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3811 |
|
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Franklin Schmidt <fschmidt@gmail.com>
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diff
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|
3812 <p> |
|
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parents:
diff
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|
3813 Userdata represent C values in Lua. |
|
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parents:
diff
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|
3814 A <em>light userdata</em> represents a pointer, a <code>void*</code>. |
|
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parents:
diff
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|
3815 It is a value (like a number): |
|
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add manual.html as copy of Lua 5.3 Reference Manual
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parents:
diff
changeset
|
3816 you do not create it, it has no individual metatable, |
|
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parents:
diff
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|
3817 and it is not collected (as it was never created). |
|
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parents:
diff
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|
3818 A light userdata is equal to "any" |
|
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parents:
diff
changeset
|
3819 light userdata with the same C address. |
|
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parents:
diff
changeset
|
3820 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3821 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3822 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3823 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3824 |
|
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diff
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|
3825 <hr><h3><a name="lua_pushliteral"><code>lua_pushliteral</code></a></h3><p> |
|
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parents:
diff
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|
3826 <span class="apii">[-0, +1, <em>e</em>]</span> |
|
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parents:
diff
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|
3827 <pre>const char *lua_pushliteral (lua_State *L, const char *s);</pre> |
|
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|
3828 |
|
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Franklin Schmidt <fschmidt@gmail.com>
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diff
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|
3829 <p> |
|
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parents:
diff
changeset
|
3830 This macro is equivalent to <a href="#lua_pushlstring"><code>lua_pushlstring</code></a>, |
|
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parents:
diff
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|
3831 but can be used only when <code>s</code> is a literal string. |
|
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parents:
diff
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|
3832 It automatically provides the string length. |
|
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parents:
diff
changeset
|
3833 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3834 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3835 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3836 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3837 |
|
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diff
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|
3838 <hr><h3><a name="lua_pushlstring"><code>lua_pushlstring</code></a></h3><p> |
|
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|
3839 <span class="apii">[-0, +1, <em>e</em>]</span> |
|
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|
3840 <pre>const char *lua_pushlstring (lua_State *L, const char *s, size_t len);</pre> |
|
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diff
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|
3841 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
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|
3842 <p> |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
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|
3843 Pushes the string pointed to by <code>s</code> with size <code>len</code> |
|
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parents:
diff
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|
3844 onto the stack. |
|
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parents:
diff
changeset
|
3845 Lua makes (or reuses) an internal copy of the given string, |
|
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parents:
diff
changeset
|
3846 so the memory at <code>s</code> can be freed or reused immediately after |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
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|
3847 the function returns. |
|
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parents:
diff
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|
3848 The string can contain any binary data, |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3849 including embedded zeros. |
|
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parents:
diff
changeset
|
3850 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3851 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3852 <p> |
|
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parents:
diff
changeset
|
3853 Returns a pointer to the internal copy of the string. |
|
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parents:
diff
changeset
|
3854 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3855 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3856 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3857 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3858 |
|
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parents:
diff
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|
3859 <hr><h3><a name="lua_pushnil"><code>lua_pushnil</code></a></h3><p> |
|
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parents:
diff
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|
3860 <span class="apii">[-0, +1, –]</span> |
|
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parents:
diff
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|
3861 <pre>void lua_pushnil (lua_State *L);</pre> |
|
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parents:
diff
changeset
|
3862 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3863 <p> |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3864 Pushes a nil value onto the stack. |
|
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parents:
diff
changeset
|
3865 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3866 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3867 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3868 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
3869 |
|
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parents:
diff
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|
3870 <hr><h3><a name="lua_pushnumber"><code>lua_pushnumber</code></a></h3><p> |
|
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|
3871 <span class="apii">[-0, +1, –]</span> |
|
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parents:
diff
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|
3872 <pre>void lua_pushnumber (lua_State *L, lua_Number n);</pre> |
|
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|
3873 |
|
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parents:
diff
changeset
|
3874 <p> |
|
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parents:
diff
changeset
|
3875 Pushes a float with value <code>n</code> onto the stack. |
|
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parents:
diff
changeset
|
3876 |
|
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parents:
diff
changeset
|
3877 |
|
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parents:
diff
changeset
|
3878 |
|
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parents:
diff
changeset
|
3879 |
|
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parents:
diff
changeset
|
3880 |
|
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diff
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|
3881 <hr><h3><a name="lua_pushstring"><code>lua_pushstring</code></a></h3><p> |
|
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|
3882 <span class="apii">[-0, +1, <em>e</em>]</span> |
|
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|
3883 <pre>const char *lua_pushstring (lua_State *L, const char *s);</pre> |
|
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|
3884 |
|
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diff
changeset
|
3885 <p> |
|
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parents:
diff
changeset
|
3886 Pushes the zero-terminated string pointed to by <code>s</code> |
|
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|
3887 onto the stack. |
|
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parents:
diff
changeset
|
3888 Lua makes (or reuses) an internal copy of the given string, |
|
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parents:
diff
changeset
|
3889 so the memory at <code>s</code> can be freed or reused immediately after |
|
e01cddba3433
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diff
changeset
|
3890 the function returns. |
|
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parents:
diff
changeset
|
3891 |
|
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diff
changeset
|
3892 |
|
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changeset
|
3893 <p> |
|
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diff
changeset
|
3894 Returns a pointer to the internal copy of the string. |
|
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parents:
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changeset
|
3895 |
|
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diff
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|
3896 |
|
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diff
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|
3897 <p> |
|
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changeset
|
3898 If <code>s</code> is <code>NULL</code>, pushes <b>nil</b> and returns <code>NULL</code>. |
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|
3899 |
|
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|
3900 |
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diff
changeset
|
3901 |
|
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|
3902 |
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|
3903 |
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|
3904 <hr><h3><a name="lua_pushthread"><code>lua_pushthread</code></a></h3><p> |
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|
3905 <span class="apii">[-0, +1, –]</span> |
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|
3906 <pre>int lua_pushthread (lua_State *L);</pre> |
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|
3907 |
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|
3908 <p> |
|
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|
3909 Pushes the thread represented by <code>L</code> onto the stack. |
|
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|
3910 Returns 1 if this thread is the main thread of its state. |
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|
3911 |
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|
3912 |
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|
3913 |
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|
3914 |
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|
3915 |
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|
3916 <hr><h3><a name="lua_pushvalue"><code>lua_pushvalue</code></a></h3><p> |
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|
3917 <span class="apii">[-0, +1, –]</span> |
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|
3918 <pre>void lua_pushvalue (lua_State *L, int index);</pre> |
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|
3919 |
|
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|
3920 <p> |
|
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|
3921 Pushes a copy of the element at the given index |
|
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|
3922 onto the stack. |
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|
3923 |
|
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|
3924 |
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|
3925 |
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|
3926 |
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changeset
|
3927 |
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|
3928 <hr><h3><a name="lua_pushvfstring"><code>lua_pushvfstring</code></a></h3><p> |
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|
3929 <span class="apii">[-0, +1, <em>e</em>]</span> |
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|
3930 <pre>const char *lua_pushvfstring (lua_State *L, |
|
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|
3931 const char *fmt, |
|
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|
3932 va_list argp);</pre> |
|
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|
3933 |
|
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|
3934 <p> |
|
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|
3935 Equivalent to <a href="#lua_pushfstring"><code>lua_pushfstring</code></a>, except that it receives a <code>va_list</code> |
|
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|
3936 instead of a variable number of arguments. |
|
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|
3937 |
|
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diff
changeset
|
3938 |
|
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diff
changeset
|
3939 |
|
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diff
changeset
|
3940 |
|
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|
3941 |
|
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|
3942 <hr><h3><a name="lua_rawequal"><code>lua_rawequal</code></a></h3><p> |
|
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|
3943 <span class="apii">[-0, +0, –]</span> |
|
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|
3944 <pre>int lua_rawequal (lua_State *L, int index1, int index2);</pre> |
|
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|
3945 |
|
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|
3946 <p> |
|
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|
3947 Returns 1 if the two values in indices <code>index1</code> and |
|
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|
3948 <code>index2</code> are primitively equal |
|
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|
3949 (that is, without calling metamethods). |
|
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|
3950 Otherwise returns 0. |
|
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|
3951 Also returns 0 if any of the indices are not valid. |
|
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|
3952 |
|
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|
3953 |
|
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diff
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|
3954 |
|
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|
3955 |
|
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|
3956 |
|
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|
3957 <hr><h3><a name="lua_rawget"><code>lua_rawget</code></a></h3><p> |
|
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|
3958 <span class="apii">[-1, +1, –]</span> |
|
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|
3959 <pre>int lua_rawget (lua_State *L, int index);</pre> |
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|
3960 |
|
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|
3961 <p> |
|
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|
3962 Similar to <a href="#lua_gettable"><code>lua_gettable</code></a>, but does a raw access |
|
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|
3963 (i.e., without metamethods). |
|
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|
3964 |
|
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changeset
|
3965 |
|
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|
3966 |
|
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|
3967 |
|
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|
3968 |
|
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|
3969 <hr><h3><a name="lua_rawgeti"><code>lua_rawgeti</code></a></h3><p> |
|
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|
3970 <span class="apii">[-0, +1, –]</span> |
|
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|
3971 <pre>int lua_rawgeti (lua_State *L, int index, lua_Integer n);</pre> |
|
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|
3972 |
|
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|
3973 <p> |
|
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|
3974 Pushes onto the stack the value <code>t[n]</code>, |
|
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|
3975 where <code>t</code> is the table at the given index. |
|
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|
3976 The access is raw; |
|
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|
3977 that is, it does not invoke metamethods. |
|
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|
3978 |
|
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diff
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|
3979 |
|
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|
3980 <p> |
|
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|
3981 Returns the type of the pushed value. |
|
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|
3982 |
|
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|
3983 |
|
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|
3984 |
|
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|
3985 |
|
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|
3986 |
|
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|
3987 <hr><h3><a name="lua_rawgetp"><code>lua_rawgetp</code></a></h3><p> |
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|
3988 <span class="apii">[-0, +1, –]</span> |
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|
3989 <pre>int lua_rawgetp (lua_State *L, int index, const void *p);</pre> |
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|
3990 |
|
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|
3991 <p> |
|
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|
3992 Pushes onto the stack the value <code>t[k]</code>, |
|
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|
3993 where <code>t</code> is the table at the given index and |
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|
3994 <code>k</code> is the pointer <code>p</code> represented as a light userdata. |
|
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3995 The access is raw; |
|
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|
3996 that is, it does not invoke metamethods. |
|
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|
3997 |
|
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|
3998 |
|
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|
3999 <p> |
|
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|
4000 Returns the type of the pushed value. |
|
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|
4001 |
|
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|
4002 |
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|
4003 |
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|
4004 |
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|
4005 |
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|
4006 <hr><h3><a name="lua_rawlen"><code>lua_rawlen</code></a></h3><p> |
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|
4007 <span class="apii">[-0, +0, –]</span> |
|
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|
4008 <pre>size_t lua_rawlen (lua_State *L, int index);</pre> |
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4009 |
|
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|
4010 <p> |
|
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|
4011 Returns the raw "length" of the value at the given index: |
|
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|
4012 for strings, this is the string length; |
|
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|
4013 for tables, this is the result of the length operator ('<code>#</code>') |
|
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4014 with no metamethods; |
|
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|
4015 for userdata, this is the size of the block of memory allocated |
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|
4016 for the userdata; |
|
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|
4017 for other values, it is 0. |
|
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|
4018 |
|
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|
4019 |
|
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|
4020 |
|
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changeset
|
4021 |
|
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changeset
|
4022 |
|
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|
4023 <hr><h3><a name="lua_rawset"><code>lua_rawset</code></a></h3><p> |
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4024 <span class="apii">[-2, +0, <em>e</em>]</span> |
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|
4025 <pre>void lua_rawset (lua_State *L, int index);</pre> |
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|
4026 |
|
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|
4027 <p> |
|
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|
4028 Similar to <a href="#lua_settable"><code>lua_settable</code></a>, but does a raw assignment |
|
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|
4029 (i.e., without metamethods). |
|
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|
4030 |
|
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changeset
|
4031 |
|
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changeset
|
4032 |
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changeset
|
4033 |
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|
4034 |
|
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|
4035 <hr><h3><a name="lua_rawseti"><code>lua_rawseti</code></a></h3><p> |
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|
4036 <span class="apii">[-1, +0, <em>e</em>]</span> |
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|
4037 <pre>void lua_rawseti (lua_State *L, int index, lua_Integer i);</pre> |
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|
4038 |
|
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|
4039 <p> |
|
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|
4040 Does the equivalent of <code>t[i] = v</code>, |
|
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|
4041 where <code>t</code> is the table at the given index |
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|
4042 and <code>v</code> is the value at the top of the stack. |
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|
4043 |
|
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changeset
|
4044 |
|
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|
4045 <p> |
|
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|
4046 This function pops the value from the stack. |
|
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|
4047 The assignment is raw; |
|
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|
4048 that is, it does not invoke metamethods. |
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|
4049 |
|
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changeset
|
4050 |
|
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changeset
|
4051 |
|
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changeset
|
4052 |
|
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changeset
|
4053 |
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|
4054 <hr><h3><a name="lua_rawsetp"><code>lua_rawsetp</code></a></h3><p> |
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|
4055 <span class="apii">[-1, +0, <em>e</em>]</span> |
|
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|
4056 <pre>void lua_rawsetp (lua_State *L, int index, const void *p);</pre> |
|
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|
4057 |
|
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|
4058 <p> |
|
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|
4059 Does the equivalent of <code>t[k] = v</code>, |
|
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|
4060 where <code>t</code> is the table at the given index, |
|
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|
4061 <code>k</code> is the pointer <code>p</code> represented as a light userdata, |
|
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|
4062 and <code>v</code> is the value at the top of the stack. |
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|
4063 |
|
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|
4064 |
|
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|
4065 <p> |
|
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|
4066 This function pops the value from the stack. |
|
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|
4067 The assignment is raw; |
|
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|
4068 that is, it does not invoke metamethods. |
|
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|
4069 |
|
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diff
changeset
|
4070 |
|
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|
4071 |
|
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|
4072 |
|
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|
4073 |
|
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|
4074 <hr><h3><a name="lua_Reader"><code>lua_Reader</code></a></h3> |
|
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|
4075 <pre>typedef const char * (*lua_Reader) (lua_State *L, |
|
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|
4076 void *data, |
|
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|
4077 size_t *size);</pre> |
|
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|
4078 |
|
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|
4079 <p> |
|
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|
4080 The reader function used by <a href="#lua_load"><code>lua_load</code></a>. |
|
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|
4081 Every time it needs another piece of the chunk, |
|
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|
4082 <a href="#lua_load"><code>lua_load</code></a> calls the reader, |
|
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|
4083 passing along its <code>data</code> parameter. |
|
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|
4084 The reader must return a pointer to a block of memory |
|
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|
4085 with a new piece of the chunk |
|
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|
4086 and set <code>size</code> to the block size. |
|
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|
4087 The block must exist until the reader function is called again. |
|
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|
4088 To signal the end of the chunk, |
|
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|
4089 the reader must return <code>NULL</code> or set <code>size</code> to zero. |
|
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changeset
|
4090 The reader function may return pieces of any size greater than zero. |
|
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changeset
|
4091 |
|
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diff
changeset
|
4092 |
|
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Franklin Schmidt <fschmidt@gmail.com>
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diff
changeset
|
4093 |
|
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diff
changeset
|
4094 |
|
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changeset
|
4095 |
|
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|
4096 <hr><h3><a name="lua_register"><code>lua_register</code></a></h3><p> |
|
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|
4097 <span class="apii">[-0, +0, <em>e</em>]</span> |
|
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|
4098 <pre>void lua_register (lua_State *L, const char *name, lua_CFunction f);</pre> |
|
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|
4099 |
|
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|
4100 <p> |
|
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|
4101 Sets the C function <code>f</code> as the new value of global <code>name</code>. |
|
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|
4102 It is defined as a macro: |
|
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|
4103 |
|
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|
4104 <pre> |
|
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|
4105 #define lua_register(L,n,f) \ |
|
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|
4106 (lua_pushcfunction(L, f), lua_setglobal(L, n)) |
|
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|
4107 </pre> |
|
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|
4108 |
|
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changeset
|
4109 |
|
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|
4110 |
|
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|
4111 |
|
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|
4112 <hr><h3><a name="lua_remove"><code>lua_remove</code></a></h3><p> |
|
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|
4113 <span class="apii">[-1, +0, –]</span> |
|
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|
4114 <pre>void lua_remove (lua_State *L, int index);</pre> |
|
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|
4115 |
|
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|
4116 <p> |
|
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|
4117 Removes the element at the given valid index, |
|
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|
4118 shifting down the elements above this index to fill the gap. |
|
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|
4119 This function cannot be called with a pseudo-index, |
|
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|
4120 because a pseudo-index is not an actual stack position. |
|
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|
4121 |
|
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|
4122 |
|
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changeset
|
4123 |
|
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|
4124 |
|
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|
4125 |
|
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|
4126 <hr><h3><a name="lua_replace"><code>lua_replace</code></a></h3><p> |
|
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|
4127 <span class="apii">[-1, +0, –]</span> |
|
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|
4128 <pre>void lua_replace (lua_State *L, int index);</pre> |
|
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|
4129 |
|
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|
4130 <p> |
|
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|
4131 Moves the top element into the given valid index |
|
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4132 without shifting any element |
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4133 (therefore replacing the value at the given index), |
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4134 and then pops the top element. |
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4135 |
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4136 |
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4137 |
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4138 |
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4139 |
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4140 <hr><h3><a name="lua_resume"><code>lua_resume</code></a></h3><p> |
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4141 <span class="apii">[-?, +?, –]</span> |
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4142 <pre>int lua_resume (lua_State *L, lua_State *from, int nargs);</pre> |
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4143 |
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4144 <p> |
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4145 Starts and resumes a coroutine in a given thread. |
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4146 |
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4147 |
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4148 <p> |
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4149 To start a coroutine, |
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4150 you push onto the thread stack the main function plus any arguments; |
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4151 then you call <a href="#lua_resume"><code>lua_resume</code></a>, |
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4152 with <code>nargs</code> being the number of arguments. |
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4153 This call returns when the coroutine suspends or finishes its execution. |
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4154 When it returns, the stack contains all values passed to <a href="#lua_yield"><code>lua_yield</code></a>, |
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4155 or all values returned by the body function. |
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4156 <a href="#lua_resume"><code>lua_resume</code></a> returns |
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4157 <a href="#pdf-LUA_YIELD"><code>LUA_YIELD</code></a> if the coroutine yields, |
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4158 <a href="#pdf-LUA_OK"><code>LUA_OK</code></a> if the coroutine finishes its execution |
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4159 without errors, |
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4160 or an error code in case of errors (see <a href="#lua_pcall"><code>lua_pcall</code></a>). |
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4161 |
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4162 |
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4163 <p> |
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4164 In case of errors, |
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4165 the stack is not unwound, |
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4166 so you can use the debug API over it. |
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4167 The error message is on the top of the stack. |
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4168 |
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4169 |
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4170 <p> |
|
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4171 To resume a coroutine, |
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4172 you remove any results from the last <a href="#lua_yield"><code>lua_yield</code></a>, |
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4173 put on its stack only the values to |
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4174 be passed as results from <code>yield</code>, |
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4175 and then call <a href="#lua_resume"><code>lua_resume</code></a>. |
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4176 |
|
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|
4177 |
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4178 <p> |
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4179 The parameter <code>from</code> represents the coroutine that is resuming <code>L</code>. |
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4180 If there is no such coroutine, |
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4181 this parameter can be <code>NULL</code>. |
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4182 |
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4183 |
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4184 |
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4185 |
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4186 |
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4187 <hr><h3><a name="lua_rotate"><code>lua_rotate</code></a></h3><p> |
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4188 <span class="apii">[-0, +0, –]</span> |
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4189 <pre>void lua_rotate (lua_State *L, int idx, int n);</pre> |
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4190 |
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4191 <p> |
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4192 Rotates the stack elements from <code>idx</code> to the top <code>n</code> positions |
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4193 in the direction of the top, for a positive <code>n</code>, |
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4194 or <code>-n</code> positions in the direction of the bottom, |
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4195 for a negative <code>n</code>. |
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4196 The absolute value of <code>n</code> must not be greater than the size |
|
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4197 of the slice being rotated. |
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4198 |
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|
4199 |
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|
4200 |
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|
4201 |
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4202 |
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4203 <hr><h3><a name="lua_setallocf"><code>lua_setallocf</code></a></h3><p> |
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4204 <span class="apii">[-0, +0, –]</span> |
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4205 <pre>void lua_setallocf (lua_State *L, lua_Alloc f, void *ud);</pre> |
|
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4206 |
|
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|
4207 <p> |
|
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|
4208 Changes the allocator function of a given state to <code>f</code> |
|
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4209 with user data <code>ud</code>. |
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4210 |
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|
4211 |
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|
4212 |
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|
4213 |
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4214 |
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4215 <hr><h3><a name="lua_setfield"><code>lua_setfield</code></a></h3><p> |
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4216 <span class="apii">[-1, +0, <em>e</em>]</span> |
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|
4217 <pre>void lua_setfield (lua_State *L, int index, const char *k);</pre> |
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4218 |
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4219 <p> |
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4220 Does the equivalent to <code>t[k] = v</code>, |
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4221 where <code>t</code> is the value at the given index |
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4222 and <code>v</code> is the value at the top of the stack. |
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4223 |
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4224 |
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4225 <p> |
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4226 This function pops the value from the stack. |
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4227 As in Lua, this function may trigger a metamethod |
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4228 for the "newindex" event (see <a href="#2.4">§2.4</a>). |
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4229 |
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4230 |
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4231 |
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4232 |
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4233 |
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4234 <hr><h3><a name="lua_setglobal"><code>lua_setglobal</code></a></h3><p> |
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4235 <span class="apii">[-1, +0, <em>e</em>]</span> |
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4236 <pre>void lua_setglobal (lua_State *L, const char *name);</pre> |
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4237 |
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4238 <p> |
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4239 Pops a value from the stack and |
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4240 sets it as the new value of global <code>name</code>. |
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4241 |
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4242 |
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4243 |
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4244 |
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4245 |
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4246 <hr><h3><a name="lua_seti"><code>lua_seti</code></a></h3><p> |
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4247 <span class="apii">[-1, +0, <em>e</em>]</span> |
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changeset
|
4248 <pre>void lua_seti (lua_State *L, int index, lua_Integer n);</pre> |
|
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|
4249 |
|
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diff
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|
4250 <p> |
|
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diff
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|
4251 Does the equivalent to <code>t[n] = v</code>, |
|
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parents:
diff
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|
4252 where <code>t</code> is the value at the given index |
|
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diff
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|
4253 and <code>v</code> is the value at the top of the stack. |
|
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|
4254 |
|
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diff
changeset
|
4255 |
|
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diff
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|
4256 <p> |
|
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|
4257 This function pops the value from the stack. |
|
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parents:
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|
4258 As in Lua, this function may trigger a metamethod |
|
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|
4259 for the "newindex" event (see <a href="#2.4">§2.4</a>). |
|
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|
4260 |
|
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diff
changeset
|
4261 |
|
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diff
changeset
|
4262 |
|
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diff
changeset
|
4263 |
|
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diff
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|
4264 |
|
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|
4265 <hr><h3><a name="lua_setmetatable"><code>lua_setmetatable</code></a></h3><p> |
|
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|
4266 <span class="apii">[-1, +0, –]</span> |
|
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|
4267 <pre>void lua_setmetatable (lua_State *L, int index);</pre> |
|
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|
4268 |
|
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diff
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|
4269 <p> |
|
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|
4270 Pops a table from the stack and |
|
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|
4271 sets it as the new metatable for the value at the given index. |
|
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|
4272 |
|
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parents:
diff
changeset
|
4273 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
4274 |
|
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Franklin Schmidt <fschmidt@gmail.com>
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diff
changeset
|
4275 |
|
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Franklin Schmidt <fschmidt@gmail.com>
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diff
changeset
|
4276 |
|
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|
4277 <hr><h3><a name="lua_settable"><code>lua_settable</code></a></h3><p> |
|
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|
4278 <span class="apii">[-2, +0, <em>e</em>]</span> |
|
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|
4279 <pre>void lua_settable (lua_State *L, int index);</pre> |
|
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|
4280 |
|
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|
4281 <p> |
|
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diff
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|
4282 Does the equivalent to <code>t[k] = v</code>, |
|
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parents:
diff
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|
4283 where <code>t</code> is the value at the given index, |
|
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|
4284 <code>v</code> is the value at the top of the stack, |
|
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diff
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|
4285 and <code>k</code> is the value just below the top. |
|
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|
4286 |
|
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Franklin Schmidt <fschmidt@gmail.com>
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diff
changeset
|
4287 |
|
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|
4288 <p> |
|
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|
4289 This function pops both the key and the value from the stack. |
|
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parents:
diff
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|
4290 As in Lua, this function may trigger a metamethod |
|
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parents:
diff
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|
4291 for the "newindex" event (see <a href="#2.4">§2.4</a>). |
|
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diff
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|
4292 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
4293 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
4294 |
|
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diff
changeset
|
4295 |
|
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Franklin Schmidt <fschmidt@gmail.com>
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diff
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|
4296 |
|
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|
4297 <hr><h3><a name="lua_settop"><code>lua_settop</code></a></h3><p> |
|
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|
4298 <span class="apii">[-?, +?, –]</span> |
|
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|
4299 <pre>void lua_settop (lua_State *L, int index);</pre> |
|
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|
4300 |
|
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diff
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|
4301 <p> |
|
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|
4302 Accepts any index, or 0, |
|
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|
4303 and sets the stack top to this index. |
|
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parents:
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|
4304 If the new top is larger than the old one, |
|
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diff
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|
4305 then the new elements are filled with <b>nil</b>. |
|
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parents:
diff
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|
4306 If <code>index</code> is 0, then all stack elements are removed. |
|
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|
4307 |
|
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diff
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|
4308 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
4309 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
4310 |
|
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Franklin Schmidt <fschmidt@gmail.com>
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diff
changeset
|
4311 |
|
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|
4312 <hr><h3><a name="lua_setuservalue"><code>lua_setuservalue</code></a></h3><p> |
|
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|
4313 <span class="apii">[-1, +0, –]</span> |
|
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|
4314 <pre>void lua_setuservalue (lua_State *L, int index);</pre> |
|
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|
4315 |
|
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diff
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|
4316 <p> |
|
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diff
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|
4317 Pops a value from the stack and sets it as |
|
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diff
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|
4318 the new value associated to the userdata at the given index. |
|
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diff
changeset
|
4319 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
4320 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
4321 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
4322 |
|
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Franklin Schmidt <fschmidt@gmail.com>
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diff
changeset
|
4323 |
|
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diff
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|
4324 <hr><h3><a name="lua_State"><code>lua_State</code></a></h3> |
|
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|
4325 <pre>typedef struct lua_State lua_State;</pre> |
|
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|
4326 |
|
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diff
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|
4327 <p> |
|
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diff
changeset
|
4328 An opaque structure that points to a thread and indirectly |
|
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diff
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|
4329 (through the thread) to the whole state of a Lua interpreter. |
|
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diff
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|
4330 The Lua library is fully reentrant: |
|
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|
4331 it has no global variables. |
|
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diff
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|
4332 All information about a state is accessible through this structure. |
|
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|
4333 |
|
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diff
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|
4334 |
|
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|
4335 <p> |
|
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|
4336 A pointer to this structure must be passed as the first argument to |
|
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|
4337 every function in the library, except to <a href="#lua_newstate"><code>lua_newstate</code></a>, |
|
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|
4338 which creates a Lua state from scratch. |
|
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|
4339 |
|
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diff
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|
4340 |
|
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|
4341 |
|
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|
4342 |
|
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|
4343 |
|
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|
4344 <hr><h3><a name="lua_status"><code>lua_status</code></a></h3><p> |
|
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|
4345 <span class="apii">[-0, +0, –]</span> |
|
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|
4346 <pre>int lua_status (lua_State *L);</pre> |
|
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|
4347 |
|
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|
4348 <p> |
|
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|
4349 Returns the status of the thread <code>L</code>. |
|
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|
4350 |
|
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|
4351 |
|
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|
4352 <p> |
|
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|
4353 The status can be 0 (<a href="#pdf-LUA_OK"><code>LUA_OK</code></a>) for a normal thread, |
|
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|
4354 an error code if the thread finished the execution |
|
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|
4355 of a <a href="#lua_resume"><code>lua_resume</code></a> with an error, |
|
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|
4356 or <a name="pdf-LUA_YIELD"><code>LUA_YIELD</code></a> if the thread is suspended. |
|
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|
4357 |
|
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|
4358 |
|
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|
4359 <p> |
|
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|
4360 You can only call functions in threads with status <a href="#pdf-LUA_OK"><code>LUA_OK</code></a>. |
|
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|
4361 You can resume threads with status <a href="#pdf-LUA_OK"><code>LUA_OK</code></a> |
|
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|
4362 (to start a new coroutine) or <a href="#pdf-LUA_YIELD"><code>LUA_YIELD</code></a> |
|
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|
4363 (to resume a coroutine). |
|
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|
4364 |
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4365 |
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4366 |
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|
4367 |
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4368 |
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4369 <hr><h3><a name="lua_stringtonumber"><code>lua_stringtonumber</code></a></h3><p> |
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4370 <span class="apii">[-0, +1, –]</span> |
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|
4371 <pre>size_t lua_stringtonumber (lua_State *L, const char *s);</pre> |
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4372 |
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4373 <p> |
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|
4374 Converts the zero-terminated string <code>s</code> to a number, |
|
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4375 pushes that number into the stack, |
|
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4376 and returns the total size of the string, |
|
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|
4377 that is, its length plus one. |
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4378 The conversion can result in an integer or a float, |
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4379 according to the lexical conventions of Lua (see <a href="#3.1">§3.1</a>). |
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4380 The string may have leading and trailing spaces and a sign. |
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4381 If the string is not a valid numeral, |
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4382 returns 0 and pushes nothing. |
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4383 (Note that the result can be used as a boolean, |
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4384 true if the conversion succeeds.) |
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4385 |
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4386 |
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4387 |
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4388 |
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4389 |
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4390 <hr><h3><a name="lua_toboolean"><code>lua_toboolean</code></a></h3><p> |
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4391 <span class="apii">[-0, +0, –]</span> |
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|
4392 <pre>int lua_toboolean (lua_State *L, int index);</pre> |
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4393 |
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4394 <p> |
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|
4395 Converts the Lua value at the given index to a C boolean |
|
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|
4396 value (0 or 1). |
|
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4397 Like all tests in Lua, |
|
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|
4398 <a href="#lua_toboolean"><code>lua_toboolean</code></a> returns true for any Lua value |
|
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|
4399 different from <b>false</b> and <b>nil</b>; |
|
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|
4400 otherwise it returns false. |
|
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|
4401 (If you want to accept only actual boolean values, |
|
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|
4402 use <a href="#lua_isboolean"><code>lua_isboolean</code></a> to test the value's type.) |
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|
4403 |
|
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|
4404 |
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|
4405 |
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|
4406 |
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|
4407 |
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4408 <hr><h3><a name="lua_tocfunction"><code>lua_tocfunction</code></a></h3><p> |
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4409 <span class="apii">[-0, +0, –]</span> |
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|
4410 <pre>lua_CFunction lua_tocfunction (lua_State *L, int index);</pre> |
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|
4411 |
|
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|
4412 <p> |
|
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|
4413 Converts a value at the given index to a C function. |
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|
4414 That value must be a C function; |
|
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|
4415 otherwise, returns <code>NULL</code>. |
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|
4416 |
|
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|
4417 |
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|
4418 |
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|
4419 |
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|
4420 |
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|
4421 <hr><h3><a name="lua_tointeger"><code>lua_tointeger</code></a></h3><p> |
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4422 <span class="apii">[-0, +0, –]</span> |
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|
4423 <pre>lua_Integer lua_tointeger (lua_State *L, int index);</pre> |
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|
4424 |
|
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|
4425 <p> |
|
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|
4426 Equivalent to <a href="#lua_tointegerx"><code>lua_tointegerx</code></a> with <code>isnum</code> equal to <code>NULL</code>. |
|
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|
4427 |
|
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|
4428 |
|
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|
4429 |
|
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|
4430 |
|
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|
4431 |
|
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|
4432 <hr><h3><a name="lua_tointegerx"><code>lua_tointegerx</code></a></h3><p> |
|
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|
4433 <span class="apii">[-0, +0, –]</span> |
|
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|
4434 <pre>lua_Integer lua_tointegerx (lua_State *L, int index, int *isnum);</pre> |
|
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|
4435 |
|
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|
4436 <p> |
|
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|
4437 Converts the Lua value at the given index |
|
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|
4438 to the signed integral type <a href="#lua_Integer"><code>lua_Integer</code></a>. |
|
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|
4439 The Lua value must be an integer, |
|
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|
4440 or a number or string convertible to an integer (see <a href="#3.4.3">§3.4.3</a>); |
|
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|
4441 otherwise, <code>lua_tointegerx</code> returns 0. |
|
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|
4442 |
|
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|
4443 |
|
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|
4444 <p> |
|
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|
4445 If <code>isnum</code> is not <code>NULL</code>, |
|
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|
4446 its referent is assigned a boolean value that |
|
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|
4447 indicates whether the operation succeeded. |
|
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|
4448 |
|
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diff
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|
4449 |
|
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|
4450 |
|
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|
4451 |
|
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|
4452 |
|
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|
4453 <hr><h3><a name="lua_tolstring"><code>lua_tolstring</code></a></h3><p> |
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|
4454 <span class="apii">[-0, +0, <em>e</em>]</span> |
|
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|
4455 <pre>const char *lua_tolstring (lua_State *L, int index, size_t *len);</pre> |
|
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|
4456 |
|
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|
4457 <p> |
|
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|
4458 Converts the Lua value at the given index to a C string. |
|
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|
4459 If <code>len</code> is not <code>NULL</code>, |
|
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|
4460 it also sets <code>*len</code> with the string length. |
|
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|
4461 The Lua value must be a string or a number; |
|
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|
4462 otherwise, the function returns <code>NULL</code>. |
|
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|
4463 If the value is a number, |
|
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|
4464 then <code>lua_tolstring</code> also |
|
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|
4465 <em>changes the actual value in the stack to a string</em>. |
|
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|
4466 (This change confuses <a href="#lua_next"><code>lua_next</code></a> |
|
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|
4467 when <code>lua_tolstring</code> is applied to keys during a table traversal.) |
|
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|
4468 |
|
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|
4469 |
|
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|
4470 <p> |
|
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|
4471 <code>lua_tolstring</code> returns a fully aligned pointer |
|
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|
4472 to a string inside the Lua state. |
|
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4473 This string always has a zero ('<code>\0</code>') |
|
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|
4474 after its last character (as in C), |
|
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|
4475 but can contain other zeros in its body. |
|
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|
4476 |
|
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|
4477 |
|
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|
4478 <p> |
|
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|
4479 Because Lua has garbage collection, |
|
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|
4480 there is no guarantee that the pointer returned by <code>lua_tolstring</code> |
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|
4481 will be valid after the corresponding Lua value is removed from the stack. |
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4482 |
|
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|
4483 |
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4484 |
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|
4485 |
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|
4486 |
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|
4487 <hr><h3><a name="lua_tonumber"><code>lua_tonumber</code></a></h3><p> |
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4488 <span class="apii">[-0, +0, –]</span> |
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|
4489 <pre>lua_Number lua_tonumber (lua_State *L, int index);</pre> |
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4490 |
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|
4491 <p> |
|
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|
4492 Equivalent to <a href="#lua_tonumberx"><code>lua_tonumberx</code></a> with <code>isnum</code> equal to <code>NULL</code>. |
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4493 |
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4494 |
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|
4495 |
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4496 |
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4497 |
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|
4498 <hr><h3><a name="lua_tonumberx"><code>lua_tonumberx</code></a></h3><p> |
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4499 <span class="apii">[-0, +0, –]</span> |
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|
4500 <pre>lua_Number lua_tonumberx (lua_State *L, int index, int *isnum);</pre> |
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4501 |
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|
4502 <p> |
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|
4503 Converts the Lua value at the given index |
|
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|
4504 to the C type <a href="#lua_Number"><code>lua_Number</code></a> (see <a href="#lua_Number"><code>lua_Number</code></a>). |
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4505 The Lua value must be a number or a string convertible to a number |
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|
4506 (see <a href="#3.4.3">§3.4.3</a>); |
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|
4507 otherwise, <a href="#lua_tonumberx"><code>lua_tonumberx</code></a> returns 0. |
|
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4508 |
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|
4509 |
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|
4510 <p> |
|
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|
4511 If <code>isnum</code> is not <code>NULL</code>, |
|
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|
4512 its referent is assigned a boolean value that |
|
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|
4513 indicates whether the operation succeeded. |
|
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4514 |
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|
4515 |
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4516 |
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|
4517 |
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4518 |
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|
4519 <hr><h3><a name="lua_topointer"><code>lua_topointer</code></a></h3><p> |
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|
4520 <span class="apii">[-0, +0, –]</span> |
|
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|
4521 <pre>const void *lua_topointer (lua_State *L, int index);</pre> |
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4522 |
|
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|
4523 <p> |
|
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|
4524 Converts the value at the given index to a generic |
|
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|
4525 C pointer (<code>void*</code>). |
|
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|
4526 The value can be a userdata, a table, a thread, or a function; |
|
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|
4527 otherwise, <code>lua_topointer</code> returns <code>NULL</code>. |
|
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|
4528 Different objects will give different pointers. |
|
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|
4529 There is no way to convert the pointer back to its original value. |
|
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|
4530 |
|
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|
4531 |
|
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|
4532 <p> |
|
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|
4533 Typically this function is used only for debug information. |
|
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|
4534 |
|
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|
4535 |
|
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|
4536 |
|
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|
4537 |
|
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|
4538 |
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|
4539 <hr><h3><a name="lua_tostring"><code>lua_tostring</code></a></h3><p> |
|
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|
4540 <span class="apii">[-0, +0, <em>e</em>]</span> |
|
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|
4541 <pre>const char *lua_tostring (lua_State *L, int index);</pre> |
|
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|
4542 |
|
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|
4543 <p> |
|
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|
4544 Equivalent to <a href="#lua_tolstring"><code>lua_tolstring</code></a> with <code>len</code> equal to <code>NULL</code>. |
|
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|
4545 |
|
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|
4546 |
|
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|
4547 |
|
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|
4548 |
|
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|
4549 |
|
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|
4550 <hr><h3><a name="lua_tothread"><code>lua_tothread</code></a></h3><p> |
|
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|
4551 <span class="apii">[-0, +0, –]</span> |
|
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|
4552 <pre>lua_State *lua_tothread (lua_State *L, int index);</pre> |
|
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|
4553 |
|
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|
4554 <p> |
|
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|
4555 Converts the value at the given index to a Lua thread |
|
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|
4556 (represented as <code>lua_State*</code>). |
|
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|
4557 This value must be a thread; |
|
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|
4558 otherwise, the function returns <code>NULL</code>. |
|
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|
4559 |
|
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diff
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|
4560 |
|
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|
4561 |
|
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|
4562 |
|
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|
4563 |
|
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|
4564 <hr><h3><a name="lua_touserdata"><code>lua_touserdata</code></a></h3><p> |
|
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|
4565 <span class="apii">[-0, +0, –]</span> |
|
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|
4566 <pre>void *lua_touserdata (lua_State *L, int index);</pre> |
|
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|
4567 |
|
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|
4568 <p> |
|
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|
4569 If the value at the given index is a full userdata, |
|
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|
4570 returns its block address. |
|
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|
4571 If the value is a light userdata, |
|
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|
4572 returns its pointer. |
|
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|
4573 Otherwise, returns <code>NULL</code>. |
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|
4574 |
|
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|
4575 |
|
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|
4576 |
|
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|
4577 |
|
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|
4578 |
|
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|
4579 <hr><h3><a name="lua_type"><code>lua_type</code></a></h3><p> |
|
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4580 <span class="apii">[-0, +0, –]</span> |
|
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|
4581 <pre>int lua_type (lua_State *L, int index);</pre> |
|
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|
4582 |
|
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|
4583 <p> |
|
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|
4584 Returns the type of the value in the given valid index, |
|
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|
4585 or <code>LUA_TNONE</code> for a non-valid (but acceptable) index. |
|
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|
4586 The types returned by <a href="#lua_type"><code>lua_type</code></a> are coded by the following constants |
|
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|
4587 defined in <code>lua.h</code>: |
|
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|
4588 <a name="pdf-LUA_TNIL"><code>LUA_TNIL</code></a>, |
|
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|
4589 <a name="pdf-LUA_TNUMBER"><code>LUA_TNUMBER</code></a>, |
|
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|
4590 <a name="pdf-LUA_TBOOLEAN"><code>LUA_TBOOLEAN</code></a>, |
|
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|
4591 <a name="pdf-LUA_TSTRING"><code>LUA_TSTRING</code></a>, |
|
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|
4592 <a name="pdf-LUA_TTABLE"><code>LUA_TTABLE</code></a>, |
|
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|
4593 <a name="pdf-LUA_TFUNCTION"><code>LUA_TFUNCTION</code></a>, |
|
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4594 <a name="pdf-LUA_TUSERDATA"><code>LUA_TUSERDATA</code></a>, |
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|
4595 <a name="pdf-LUA_TTHREAD"><code>LUA_TTHREAD</code></a>, |
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4596 and |
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|
4597 <a name="pdf-LUA_TLIGHTUSERDATA"><code>LUA_TLIGHTUSERDATA</code></a>. |
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4598 |
|
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|
4599 |
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4600 |
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4601 |
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4602 |
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4603 <hr><h3><a name="lua_typename"><code>lua_typename</code></a></h3><p> |
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4604 <span class="apii">[-0, +0, –]</span> |
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4605 <pre>const char *lua_typename (lua_State *L, int tp);</pre> |
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4606 |
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4607 <p> |
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|
4608 Returns the name of the type encoded by the value <code>tp</code>, |
|
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4609 which must be one the values returned by <a href="#lua_type"><code>lua_type</code></a>. |
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4610 |
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4611 |
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4612 |
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4613 |
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4614 |
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4615 <hr><h3><a name="lua_Unsigned"><code>lua_Unsigned</code></a></h3> |
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4616 <pre>typedef ... lua_Unsigned;</pre> |
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4617 |
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4618 <p> |
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4619 The unsigned version of <a href="#lua_Integer"><code>lua_Integer</code></a>. |
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4620 |
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4621 |
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4622 |
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4623 |
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4624 |
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4625 <hr><h3><a name="lua_upvalueindex"><code>lua_upvalueindex</code></a></h3><p> |
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4626 <span class="apii">[-0, +0, –]</span> |
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4627 <pre>int lua_upvalueindex (int i);</pre> |
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4628 |
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4629 <p> |
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4630 Returns the pseudo-index that represents the <code>i</code>-th upvalue of |
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4631 the running function (see <a href="#4.4">§4.4</a>). |
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4632 |
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|
4633 |
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|
4634 |
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4635 |
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4636 |
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4637 <hr><h3><a name="lua_version"><code>lua_version</code></a></h3><p> |
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4638 <span class="apii">[-0, +0, <em>v</em>]</span> |
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|
4639 <pre>const lua_Number *lua_version (lua_State *L);</pre> |
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4640 |
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|
4641 <p> |
|
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|
4642 Returns the address of the version number stored in the Lua core. |
|
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|
4643 When called with a valid <a href="#lua_State"><code>lua_State</code></a>, |
|
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4644 returns the address of the version used to create that state. |
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4645 When called with <code>NULL</code>, |
|
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4646 returns the address of the version running the call. |
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4647 |
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4648 |
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4649 |
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4650 |
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4651 |
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4652 <hr><h3><a name="lua_Writer"><code>lua_Writer</code></a></h3> |
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|
4653 <pre>typedef int (*lua_Writer) (lua_State *L, |
|
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|
4654 const void* p, |
|
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4655 size_t sz, |
|
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|
4656 void* ud);</pre> |
|
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4657 |
|
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|
4658 <p> |
|
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|
4659 The type of the writer function used by <a href="#lua_dump"><code>lua_dump</code></a>. |
|
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4660 Every time it produces another piece of chunk, |
|
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|
4661 <a href="#lua_dump"><code>lua_dump</code></a> calls the writer, |
|
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|
4662 passing along the buffer to be written (<code>p</code>), |
|
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4663 its size (<code>sz</code>), |
|
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|
4664 and the <code>data</code> parameter supplied to <a href="#lua_dump"><code>lua_dump</code></a>. |
|
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|
4665 |
|
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|
4666 |
|
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|
4667 <p> |
|
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|
4668 The writer returns an error code: |
|
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|
4669 0 means no errors; |
|
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|
4670 any other value means an error and stops <a href="#lua_dump"><code>lua_dump</code></a> from |
|
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|
4671 calling the writer again. |
|
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|
4672 |
|
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|
4673 |
|
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|
4674 |
|
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|
4675 |
|
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|
4676 |
|
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4677 <hr><h3><a name="lua_xmove"><code>lua_xmove</code></a></h3><p> |
|
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4678 <span class="apii">[-?, +?, –]</span> |
|
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|
4679 <pre>void lua_xmove (lua_State *from, lua_State *to, int n);</pre> |
|
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4680 |
|
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4681 <p> |
|
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4682 Exchange values between different threads of the same state. |
|
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4683 |
|
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|
4684 |
|
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4685 <p> |
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|
4686 This function pops <code>n</code> values from the stack <code>from</code>, |
|
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4687 and pushes them onto the stack <code>to</code>. |
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4688 |
|
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|
4689 |
|
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|
4690 |
|
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|
4691 |
|
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4692 |
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4693 <hr><h3><a name="lua_yield"><code>lua_yield</code></a></h3><p> |
|
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4694 <span class="apii">[-?, +?, <em>e</em>]</span> |
|
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4695 <pre>int lua_yield (lua_State *L, int nresults);</pre> |
|
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4696 |
|
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4697 <p> |
|
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4698 This function is equivalent to <a href="#lua_yieldk"><code>lua_yieldk</code></a>, |
|
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4699 but it has no continuation (see <a href="#4.7">§4.7</a>). |
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4700 Therefore, when the thread resumes, |
|
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4701 it continues the function that called |
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4702 the function calling <code>lua_yield</code>. |
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4703 |
|
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|
4704 |
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|
4705 |
|
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|
4706 |
|
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4707 |
|
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4708 <hr><h3><a name="lua_yieldk"><code>lua_yieldk</code></a></h3><p> |
|
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4709 <span class="apii">[-?, +?, <em>e</em>]</span> |
|
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4710 <pre>int lua_yieldk (lua_State *L, |
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4711 int nresults, |
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4712 lua_KContext ctx, |
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|
4713 lua_KFunction k);</pre> |
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4714 |
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4715 <p> |
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4716 Yields a coroutine (thread). |
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4717 |
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4718 |
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4719 <p> |
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4720 When a C function calls <a href="#lua_yieldk"><code>lua_yieldk</code></a>, |
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4721 the running coroutine suspends its execution, |
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4722 and the call to <a href="#lua_resume"><code>lua_resume</code></a> that started this coroutine returns. |
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4723 The parameter <code>nresults</code> is the number of values from the stack |
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4724 that will be passed as results to <a href="#lua_resume"><code>lua_resume</code></a>. |
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4725 |
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4726 |
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4727 <p> |
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4728 When the coroutine is resumed again, |
|
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4729 Lua calls the given continuation function <code>k</code> to continue |
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4730 the execution of the C function that yielded (see <a href="#4.7">§4.7</a>). |
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4731 This continuation function receives the same stack |
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4732 from the previous function, |
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4733 with the <code>n</code> results removed and |
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4734 replaced by the arguments passed to <a href="#lua_resume"><code>lua_resume</code></a>. |
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4735 Moreover, |
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4736 the continuation function receives the value <code>ctx</code> |
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4737 that was passed to <a href="#lua_yieldk"><code>lua_yieldk</code></a>. |
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4738 |
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4739 |
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4740 <p> |
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4741 Usually, this function does not return; |
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4742 when the coroutine eventually resumes, |
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4743 it continues executing the continuation function. |
|
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4744 However, there is one special case, |
|
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4745 which is when this function is called |
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4746 from inside a line hook (see <a href="#4.9">§4.9</a>). |
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4747 In that case, <code>lua_yieldk</code> should be called with no continuation |
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4748 (probably in the form of <a href="#lua_yield"><code>lua_yield</code></a>), |
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4749 and the hook should return immediately after the call. |
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4750 Lua will yield and, |
|
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|
4751 when the coroutine resumes again, |
|
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|
4752 it will continue the normal execution |
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4753 of the (Lua) function that triggered the hook. |
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4754 |
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4755 |
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|
4756 <p> |
|
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|
4757 This function can raise an error if it is called from a thread |
|
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4758 with a pending C call with no continuation function, |
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4759 or it is called from a thread that is not running inside a resume |
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4760 (e.g., the main thread). |
|
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4761 |
|
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|
4762 |
|
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|
4763 |
|
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|
4764 |
|
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|
4765 |
|
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|
4766 |
|
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4767 |
|
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|
4768 <h2>4.9 – <a name="4.9">The Debug Interface</a></h2> |
|
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4769 |
|
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|
4770 <p> |
|
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|
4771 Lua has no built-in debugging facilities. |
|
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|
4772 Instead, it offers a special interface |
|
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|
4773 by means of functions and <em>hooks</em>. |
|
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|
4774 This interface allows the construction of different |
|
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|
4775 kinds of debuggers, profilers, and other tools |
|
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|
4776 that need "inside information" from the interpreter. |
|
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|
4777 |
|
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|
4778 |
|
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|
4779 |
|
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|
4780 <hr><h3><a name="lua_Debug"><code>lua_Debug</code></a></h3> |
|
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|
4781 <pre>typedef struct lua_Debug { |
|
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|
4782 int event; |
|
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|
4783 const char *name; /* (n) */ |
|
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|
4784 const char *namewhat; /* (n) */ |
|
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|
4785 const char *what; /* (S) */ |
|
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|
4786 const char *source; /* (S) */ |
|
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|
4787 int currentline; /* (l) */ |
|
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|
4788 int linedefined; /* (S) */ |
|
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|
4789 int lastlinedefined; /* (S) */ |
|
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|
4790 unsigned char nups; /* (u) number of upvalues */ |
|
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|
4791 unsigned char nparams; /* (u) number of parameters */ |
|
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|
4792 char isvararg; /* (u) */ |
|
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|
4793 char istailcall; /* (t) */ |
|
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|
4794 char short_src[LUA_IDSIZE]; /* (S) */ |
|
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|
4795 /* private part */ |
|
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|
4796 <em>other fields</em> |
|
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|
4797 } lua_Debug;</pre> |
|
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|
4798 |
|
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|
4799 <p> |
|
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|
4800 A structure used to carry different pieces of |
|
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|
4801 information about a function or an activation record. |
|
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|
4802 <a href="#lua_getstack"><code>lua_getstack</code></a> fills only the private part |
|
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4803 of this structure, for later use. |
|
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|
4804 To fill the other fields of <a href="#lua_Debug"><code>lua_Debug</code></a> with useful information, |
|
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4805 call <a href="#lua_getinfo"><code>lua_getinfo</code></a>. |
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4806 |
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|
4807 |
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4808 <p> |
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|
4809 The fields of <a href="#lua_Debug"><code>lua_Debug</code></a> have the following meaning: |
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4810 |
|
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|
4811 <ul> |
|
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|
4812 |
|
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4813 <li><b><code>source</code>: </b> |
|
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4814 the name of the chunk that created the function. |
|
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4815 If <code>source</code> starts with a '<code>@</code>', |
|
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4816 it means that the function was defined in a file where |
|
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4817 the file name follows the '<code>@</code>'. |
|
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4818 If <code>source</code> starts with a '<code>=</code>', |
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4819 the remainder of its contents describe the source in a user-dependent manner. |
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4820 Otherwise, |
|
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|
4821 the function was defined in a string where |
|
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4822 <code>source</code> is that string. |
|
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4823 </li> |
|
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4824 |
|
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4825 <li><b><code>short_src</code>: </b> |
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4826 a "printable" version of <code>source</code>, to be used in error messages. |
|
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|
4827 </li> |
|
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diff
changeset
|
4828 |
|
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|
4829 <li><b><code>linedefined</code>: </b> |
|
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|
4830 the line number where the definition of the function starts. |
|
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diff
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|
4831 </li> |
|
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diff
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|
4832 |
|
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|
4833 <li><b><code>lastlinedefined</code>: </b> |
|
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|
4834 the line number where the definition of the function ends. |
|
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|
4835 </li> |
|
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diff
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|
4836 |
|
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|
4837 <li><b><code>what</code>: </b> |
|
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|
4838 the string <code>"Lua"</code> if the function is a Lua function, |
|
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|
4839 <code>"C"</code> if it is a C function, |
|
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|
4840 <code>"main"</code> if it is the main part of a chunk. |
|
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|
4841 </li> |
|
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diff
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|
4842 |
|
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|
4843 <li><b><code>currentline</code>: </b> |
|
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|
4844 the current line where the given function is executing. |
|
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|
4845 When no line information is available, |
|
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|
4846 <code>currentline</code> is set to -1. |
|
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|
4847 </li> |
|
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diff
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|
4848 |
|
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|
4849 <li><b><code>name</code>: </b> |
|
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|
4850 a reasonable name for the given function. |
|
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|
4851 Because functions in Lua are first-class values, |
|
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|
4852 they do not have a fixed name: |
|
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|
4853 some functions can be the value of multiple global variables, |
|
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|
4854 while others can be stored only in a table field. |
|
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|
4855 The <code>lua_getinfo</code> function checks how the function was |
|
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|
4856 called to find a suitable name. |
|
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|
4857 If it cannot find a name, |
|
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|
4858 then <code>name</code> is set to <code>NULL</code>. |
|
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|
4859 </li> |
|
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diff
changeset
|
4860 |
|
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diff
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|
4861 <li><b><code>namewhat</code>: </b> |
|
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|
4862 explains the <code>name</code> field. |
|
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|
4863 The value of <code>namewhat</code> can be |
|
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diff
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|
4864 <code>"global"</code>, <code>"local"</code>, <code>"method"</code>, |
|
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|
4865 <code>"field"</code>, <code>"upvalue"</code>, or <code>""</code> (the empty string), |
|
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|
4866 according to how the function was called. |
|
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|
4867 (Lua uses the empty string when no other option seems to apply.) |
|
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|
4868 </li> |
|
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diff
changeset
|
4869 |
|
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|
4870 <li><b><code>istailcall</code>: </b> |
|
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|
4871 true if this function invocation was called by a tail call. |
|
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diff
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|
4872 In this case, the caller of this level is not in the stack. |
|
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|
4873 </li> |
|
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diff
changeset
|
4874 |
|
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|
4875 <li><b><code>nups</code>: </b> |
|
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|
4876 the number of upvalues of the function. |
|
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diff
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|
4877 </li> |
|
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diff
changeset
|
4878 |
|
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|
4879 <li><b><code>nparams</code>: </b> |
|
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|
4880 the number of fixed parameters of the function |
|
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diff
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|
4881 (always 0 for C functions). |
|
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|
4882 </li> |
|
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|
4883 |
|
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|
4884 <li><b><code>isvararg</code>: </b> |
|
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|
4885 true if the function is a vararg function |
|
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diff
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|
4886 (always true for C functions). |
|
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|
4887 </li> |
|
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diff
changeset
|
4888 |
|
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diff
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|
4889 </ul> |
|
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diff
changeset
|
4890 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
4891 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
4892 |
|
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Franklin Schmidt <fschmidt@gmail.com>
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diff
changeset
|
4893 |
|
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diff
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|
4894 <hr><h3><a name="lua_gethook"><code>lua_gethook</code></a></h3><p> |
|
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|
4895 <span class="apii">[-0, +0, –]</span> |
|
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|
4896 <pre>lua_Hook lua_gethook (lua_State *L);</pre> |
|
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|
4897 |
|
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diff
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|
4898 <p> |
|
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diff
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|
4899 Returns the current hook function. |
|
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|
4900 |
|
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diff
changeset
|
4901 |
|
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Franklin Schmidt <fschmidt@gmail.com>
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diff
changeset
|
4902 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
4903 |
|
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Franklin Schmidt <fschmidt@gmail.com>
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diff
changeset
|
4904 |
|
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|
4905 <hr><h3><a name="lua_gethookcount"><code>lua_gethookcount</code></a></h3><p> |
|
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|
4906 <span class="apii">[-0, +0, –]</span> |
|
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|
4907 <pre>int lua_gethookcount (lua_State *L);</pre> |
|
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changeset
|
4908 |
|
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diff
changeset
|
4909 <p> |
|
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parents:
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changeset
|
4910 Returns the current hook count. |
|
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changeset
|
4911 |
|
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diff
changeset
|
4912 |
|
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diff
changeset
|
4913 |
|
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diff
changeset
|
4914 |
|
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changeset
|
4915 |
|
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|
4916 <hr><h3><a name="lua_gethookmask"><code>lua_gethookmask</code></a></h3><p> |
|
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|
4917 <span class="apii">[-0, +0, –]</span> |
|
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|
4918 <pre>int lua_gethookmask (lua_State *L);</pre> |
|
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|
4919 |
|
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|
4920 <p> |
|
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|
4921 Returns the current hook mask. |
|
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changeset
|
4922 |
|
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diff
changeset
|
4923 |
|
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changeset
|
4924 |
|
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changeset
|
4925 |
|
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|
4926 |
|
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|
4927 <hr><h3><a name="lua_getinfo"><code>lua_getinfo</code></a></h3><p> |
|
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|
4928 <span class="apii">[-(0|1), +(0|1|2), <em>e</em>]</span> |
|
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|
4929 <pre>int lua_getinfo (lua_State *L, const char *what, lua_Debug *ar);</pre> |
|
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|
4930 |
|
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|
4931 <p> |
|
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changeset
|
4932 Gets information about a specific function or function invocation. |
|
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changeset
|
4933 |
|
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changeset
|
4934 |
|
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|
4935 <p> |
|
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changeset
|
4936 To get information about a function invocation, |
|
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|
4937 the parameter <code>ar</code> must be a valid activation record that was |
|
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|
4938 filled by a previous call to <a href="#lua_getstack"><code>lua_getstack</code></a> or |
|
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|
4939 given as argument to a hook (see <a href="#lua_Hook"><code>lua_Hook</code></a>). |
|
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|
4940 |
|
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changeset
|
4941 |
|
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|
4942 <p> |
|
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|
4943 To get information about a function you push it onto the stack |
|
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changeset
|
4944 and start the <code>what</code> string with the character '<code>></code>'. |
|
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|
4945 (In that case, |
|
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|
4946 <code>lua_getinfo</code> pops the function from the top of the stack.) |
|
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|
4947 For instance, to know in which line a function <code>f</code> was defined, |
|
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|
4948 you can write the following code: |
|
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4949 |
|
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|
4950 <pre> |
|
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4951 lua_Debug ar; |
|
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|
4952 lua_getglobal(L, "f"); /* get global 'f' */ |
|
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4953 lua_getinfo(L, ">S", &ar); |
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4954 printf("%d\n", ar.linedefined); |
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|
4955 </pre> |
|
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4956 |
|
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4957 <p> |
|
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4958 Each character in the string <code>what</code> |
|
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4959 selects some fields of the structure <code>ar</code> to be filled or |
|
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4960 a value to be pushed on the stack: |
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4961 |
|
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|
4962 <ul> |
|
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4963 |
|
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4964 <li><b>'<code>n</code>': </b> fills in the field <code>name</code> and <code>namewhat</code>; |
|
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4965 </li> |
|
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4966 |
|
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4967 <li><b>'<code>S</code>': </b> |
|
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4968 fills in the fields <code>source</code>, <code>short_src</code>, |
|
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4969 <code>linedefined</code>, <code>lastlinedefined</code>, and <code>what</code>; |
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4970 </li> |
|
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4971 |
|
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4972 <li><b>'<code>l</code>': </b> fills in the field <code>currentline</code>; |
|
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4973 </li> |
|
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4974 |
|
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|
4975 <li><b>'<code>t</code>': </b> fills in the field <code>istailcall</code>; |
|
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|
4976 </li> |
|
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|
4977 |
|
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|
4978 <li><b>'<code>u</code>': </b> fills in the fields |
|
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|
4979 <code>nups</code>, <code>nparams</code>, and <code>isvararg</code>; |
|
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|
4980 </li> |
|
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|
4981 |
|
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|
4982 <li><b>'<code>f</code>': </b> |
|
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|
4983 pushes onto the stack the function that is |
|
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|
4984 running at the given level; |
|
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|
4985 </li> |
|
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|
4986 |
|
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|
4987 <li><b>'<code>L</code>': </b> |
|
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|
4988 pushes onto the stack a table whose indices are the |
|
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|
4989 numbers of the lines that are valid on the function. |
|
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|
4990 (A <em>valid line</em> is a line with some associated code, |
|
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|
4991 that is, a line where you can put a break point. |
|
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|
4992 Non-valid lines include empty lines and comments.) |
|
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|
4993 |
|
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|
4994 |
|
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|
4995 <p> |
|
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|
4996 If this option is given together with option '<code>f</code>', |
|
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4997 its table is pushed after the function. |
|
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|
4998 </li> |
|
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|
4999 |
|
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|
5000 </ul> |
|
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|
5001 |
|
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|
5002 <p> |
|
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|
5003 This function returns 0 on error |
|
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|
5004 (for instance, an invalid option in <code>what</code>). |
|
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|
5005 |
|
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|
5006 |
|
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|
5007 |
|
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|
5008 |
|
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|
5009 |
|
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|
5010 <hr><h3><a name="lua_getlocal"><code>lua_getlocal</code></a></h3><p> |
|
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|
5011 <span class="apii">[-0, +(0|1), –]</span> |
|
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|
5012 <pre>const char *lua_getlocal (lua_State *L, const lua_Debug *ar, int n);</pre> |
|
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|
5013 |
|
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|
5014 <p> |
|
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|
5015 Gets information about a local variable of |
|
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|
5016 a given activation record or a given function. |
|
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|
5017 |
|
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|
5018 |
|
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|
5019 <p> |
|
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|
5020 In the first case, |
|
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|
5021 the parameter <code>ar</code> must be a valid activation record that was |
|
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|
5022 filled by a previous call to <a href="#lua_getstack"><code>lua_getstack</code></a> or |
|
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|
5023 given as argument to a hook (see <a href="#lua_Hook"><code>lua_Hook</code></a>). |
|
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|
5024 The index <code>n</code> selects which local variable to inspect; |
|
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|
5025 see <a href="#pdf-debug.getlocal"><code>debug.getlocal</code></a> for details about variable indices |
|
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|
5026 and names. |
|
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|
5027 |
|
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|
5028 |
|
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|
5029 <p> |
|
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|
5030 <a href="#lua_getlocal"><code>lua_getlocal</code></a> pushes the variable's value onto the stack |
|
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|
5031 and returns its name. |
|
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|
5032 |
|
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|
5033 |
|
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|
5034 <p> |
|
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|
5035 In the second case, <code>ar</code> must be <code>NULL</code> and the function |
|
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|
5036 to be inspected must be at the top of the stack. |
|
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|
5037 In this case, only parameters of Lua functions are visible |
|
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|
5038 (as there is no information about what variables are active) |
|
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|
5039 and no values are pushed onto the stack. |
|
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|
5040 |
|
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|
5041 |
|
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|
5042 <p> |
|
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|
5043 Returns <code>NULL</code> (and pushes nothing) |
|
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|
5044 when the index is greater than |
|
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|
5045 the number of active local variables. |
|
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|
5046 |
|
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|
5047 |
|
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|
5048 |
|
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|
5049 |
|
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changeset
|
5050 |
|
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|
5051 <hr><h3><a name="lua_getstack"><code>lua_getstack</code></a></h3><p> |
|
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|
5052 <span class="apii">[-0, +0, –]</span> |
|
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|
5053 <pre>int lua_getstack (lua_State *L, int level, lua_Debug *ar);</pre> |
|
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|
5054 |
|
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|
5055 <p> |
|
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|
5056 Gets information about the interpreter runtime stack. |
|
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|
5057 |
|
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changeset
|
5058 |
|
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|
5059 <p> |
|
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|
5060 This function fills parts of a <a href="#lua_Debug"><code>lua_Debug</code></a> structure with |
|
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|
5061 an identification of the <em>activation record</em> |
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5062 of the function executing at a given level. |
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5063 Level 0 is the current running function, |
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5064 whereas level <em>n+1</em> is the function that has called level <em>n</em> |
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5065 (except for tail calls, which do not count on the stack). |
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5066 When there are no errors, <a href="#lua_getstack"><code>lua_getstack</code></a> returns 1; |
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5067 when called with a level greater than the stack depth, |
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5068 it returns 0. |
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5069 |
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5070 |
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5071 |
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5072 |
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5073 |
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5074 <hr><h3><a name="lua_getupvalue"><code>lua_getupvalue</code></a></h3><p> |
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5075 <span class="apii">[-0, +(0|1), –]</span> |
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5076 <pre>const char *lua_getupvalue (lua_State *L, int funcindex, int n);</pre> |
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5077 |
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5078 <p> |
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5079 Gets information about a closure's upvalue. |
|
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5080 (For Lua functions, |
|
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5081 upvalues are the external local variables that the function uses, |
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5082 and that are consequently included in its closure.) |
|
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5083 <a href="#lua_getupvalue"><code>lua_getupvalue</code></a> gets the index <code>n</code> of an upvalue, |
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5084 pushes the upvalue's value onto the stack, |
|
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5085 and returns its name. |
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5086 <code>funcindex</code> points to the closure in the stack. |
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5087 (Upvalues have no particular order, |
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5088 as they are active through the whole function. |
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5089 So, they are numbered in an arbitrary order.) |
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5090 |
|
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5091 |
|
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5092 <p> |
|
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5093 Returns <code>NULL</code> (and pushes nothing) |
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5094 when the index is greater than the number of upvalues. |
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5095 For C functions, this function uses the empty string <code>""</code> |
|
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5096 as a name for all upvalues. |
|
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5097 |
|
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|
5098 |
|
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|
5099 |
|
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|
5100 |
|
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|
5101 |
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5102 <hr><h3><a name="lua_Hook"><code>lua_Hook</code></a></h3> |
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5103 <pre>typedef void (*lua_Hook) (lua_State *L, lua_Debug *ar);</pre> |
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5104 |
|
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5105 <p> |
|
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5106 Type for debugging hook functions. |
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5107 |
|
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5108 |
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5109 <p> |
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5110 Whenever a hook is called, its <code>ar</code> argument has its field |
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5111 <code>event</code> set to the specific event that triggered the hook. |
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5112 Lua identifies these events with the following constants: |
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5113 <a name="pdf-LUA_HOOKCALL"><code>LUA_HOOKCALL</code></a>, <a name="pdf-LUA_HOOKRET"><code>LUA_HOOKRET</code></a>, |
|
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5114 <a name="pdf-LUA_HOOKTAILCALL"><code>LUA_HOOKTAILCALL</code></a>, <a name="pdf-LUA_HOOKLINE"><code>LUA_HOOKLINE</code></a>, |
|
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5115 and <a name="pdf-LUA_HOOKCOUNT"><code>LUA_HOOKCOUNT</code></a>. |
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5116 Moreover, for line events, the field <code>currentline</code> is also set. |
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5117 To get the value of any other field in <code>ar</code>, |
|
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5118 the hook must call <a href="#lua_getinfo"><code>lua_getinfo</code></a>. |
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5119 |
|
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5120 |
|
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5121 <p> |
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5122 For call events, <code>event</code> can be <code>LUA_HOOKCALL</code>, |
|
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5123 the normal value, or <code>LUA_HOOKTAILCALL</code>, for a tail call; |
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5124 in this case, there will be no corresponding return event. |
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5125 |
|
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5126 |
|
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5127 <p> |
|
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5128 While Lua is running a hook, it disables other calls to hooks. |
|
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|
5129 Therefore, if a hook calls back Lua to execute a function or a chunk, |
|
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5130 this execution occurs without any calls to hooks. |
|
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5131 |
|
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5132 |
|
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5133 <p> |
|
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5134 Hook functions cannot have continuations, |
|
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|
5135 that is, they cannot call <a href="#lua_yieldk"><code>lua_yieldk</code></a>, |
|
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5136 <a href="#lua_pcallk"><code>lua_pcallk</code></a>, or <a href="#lua_callk"><code>lua_callk</code></a> with a non-null <code>k</code>. |
|
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5137 |
|
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5138 |
|
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5139 <p> |
|
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5140 Hook functions can yield under the following conditions: |
|
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|
5141 Only count and line events can yield |
|
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5142 and they cannot yield any value; |
|
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5143 to yield a hook function must finish its execution |
|
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5144 calling <a href="#lua_yield"><code>lua_yield</code></a> with <code>nresults</code> equal to zero. |
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5145 |
|
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5146 |
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5147 |
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5148 |
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5149 |
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5150 <hr><h3><a name="lua_sethook"><code>lua_sethook</code></a></h3><p> |
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5151 <span class="apii">[-0, +0, –]</span> |
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5152 <pre>void lua_sethook (lua_State *L, lua_Hook f, int mask, int count);</pre> |
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5153 |
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5154 <p> |
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5155 Sets the debugging hook function. |
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5156 |
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5157 |
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5158 <p> |
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5159 Argument <code>f</code> is the hook function. |
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5160 <code>mask</code> specifies on which events the hook will be called: |
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5161 it is formed by a bitwise or of the constants |
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5162 <a name="pdf-LUA_MASKCALL"><code>LUA_MASKCALL</code></a>, |
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5163 <a name="pdf-LUA_MASKRET"><code>LUA_MASKRET</code></a>, |
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5164 <a name="pdf-LUA_MASKLINE"><code>LUA_MASKLINE</code></a>, |
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5165 and <a name="pdf-LUA_MASKCOUNT"><code>LUA_MASKCOUNT</code></a>. |
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5166 The <code>count</code> argument is only meaningful when the mask |
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5167 includes <code>LUA_MASKCOUNT</code>. |
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5168 For each event, the hook is called as explained below: |
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5169 |
|
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5170 <ul> |
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5171 |
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5172 <li><b>The call hook: </b> is called when the interpreter calls a function. |
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5173 The hook is called just after Lua enters the new function, |
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5174 before the function gets its arguments. |
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5175 </li> |
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5176 |
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5177 <li><b>The return hook: </b> is called when the interpreter returns from a function. |
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5178 The hook is called just before Lua leaves the function. |
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5179 There is no standard way to access the values |
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5180 to be returned by the function. |
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5181 </li> |
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5182 |
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5183 <li><b>The line hook: </b> is called when the interpreter is about to |
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5184 start the execution of a new line of code, |
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5185 or when it jumps back in the code (even to the same line). |
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5186 (This event only happens while Lua is executing a Lua function.) |
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5187 </li> |
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5188 |
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5189 <li><b>The count hook: </b> is called after the interpreter executes every |
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5190 <code>count</code> instructions. |
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5191 (This event only happens while Lua is executing a Lua function.) |
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5192 </li> |
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5193 |
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5194 </ul> |
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5195 |
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5196 <p> |
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5197 A hook is disabled by setting <code>mask</code> to zero. |
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5198 |
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5199 |
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5200 |
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5201 |
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5202 |
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5203 <hr><h3><a name="lua_setlocal"><code>lua_setlocal</code></a></h3><p> |
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5204 <span class="apii">[-(0|1), +0, –]</span> |
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5205 <pre>const char *lua_setlocal (lua_State *L, const lua_Debug *ar, int n);</pre> |
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5206 |
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5207 <p> |
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5208 Sets the value of a local variable of a given activation record. |
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5209 Parameters <code>ar</code> and <code>n</code> are as in <a href="#lua_getlocal"><code>lua_getlocal</code></a> |
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5210 (see <a href="#lua_getlocal"><code>lua_getlocal</code></a>). |
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5211 <a href="#lua_setlocal"><code>lua_setlocal</code></a> assigns the value at the top of the stack |
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5212 to the variable and returns its name. |
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5213 It also pops the value from the stack. |
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5214 |
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5215 |
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5216 <p> |
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5217 Returns <code>NULL</code> (and pops nothing) |
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5218 when the index is greater than |
|
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5219 the number of active local variables. |
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5220 |
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5221 |
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5222 |
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5223 |
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5224 |
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5225 <hr><h3><a name="lua_setupvalue"><code>lua_setupvalue</code></a></h3><p> |
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5226 <span class="apii">[-(0|1), +0, –]</span> |
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5227 <pre>const char *lua_setupvalue (lua_State *L, int funcindex, int n);</pre> |
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5228 |
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5229 <p> |
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5230 Sets the value of a closure's upvalue. |
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5231 It assigns the value at the top of the stack |
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5232 to the upvalue and returns its name. |
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5233 It also pops the value from the stack. |
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5234 Parameters <code>funcindex</code> and <code>n</code> are as in the <a href="#lua_getupvalue"><code>lua_getupvalue</code></a> |
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5235 (see <a href="#lua_getupvalue"><code>lua_getupvalue</code></a>). |
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5236 |
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5237 |
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5238 <p> |
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5239 Returns <code>NULL</code> (and pops nothing) |
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5240 when the index is greater than the number of upvalues. |
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5241 |
|
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5242 |
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5243 |
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5244 |
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5245 |
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5246 <hr><h3><a name="lua_upvalueid"><code>lua_upvalueid</code></a></h3><p> |
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5247 <span class="apii">[-0, +0, –]</span> |
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5248 <pre>void *lua_upvalueid (lua_State *L, int funcindex, int n);</pre> |
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5249 |
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5250 <p> |
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5251 Returns a unique identifier for the upvalue numbered <code>n</code> |
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5252 from the closure at index <code>funcindex</code>. |
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5253 Parameters <code>funcindex</code> and <code>n</code> are as in the <a href="#lua_getupvalue"><code>lua_getupvalue</code></a> |
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5254 (see <a href="#lua_getupvalue"><code>lua_getupvalue</code></a>) |
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5255 (but <code>n</code> cannot be greater than the number of upvalues). |
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5256 |
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5257 |
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5258 <p> |
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5259 These unique identifiers allow a program to check whether different |
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5260 closures share upvalues. |
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5261 Lua closures that share an upvalue |
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5262 (that is, that access a same external local variable) |
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5263 will return identical ids for those upvalue indices. |
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5264 |
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5265 |
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5266 |
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5267 |
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5268 |
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5269 <hr><h3><a name="lua_upvaluejoin"><code>lua_upvaluejoin</code></a></h3><p> |
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5270 <span class="apii">[-0, +0, –]</span> |
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5271 <pre>void lua_upvaluejoin (lua_State *L, int funcindex1, int n1, |
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5272 int funcindex2, int n2);</pre> |
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5273 |
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5274 <p> |
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5275 Make the <code>n1</code>-th upvalue of the Lua closure at index <code>funcindex1</code> |
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5276 refer to the <code>n2</code>-th upvalue of the Lua closure at index <code>funcindex2</code>. |
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5277 |
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5278 |
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5279 |
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5280 |
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5281 |
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5282 |
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5283 |
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5284 <h1>5 – <a name="5">The Auxiliary Library</a></h1> |
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5285 |
|
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5286 <p> |
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5287 |
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5288 The <em>auxiliary library</em> provides several convenient functions |
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5289 to interface C with Lua. |
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5290 While the basic API provides the primitive functions for all |
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|
5291 interactions between C and Lua, |
|
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|
5292 the auxiliary library provides higher-level functions for some |
|
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|
5293 common tasks. |
|
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|
5294 |
|
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|
5295 |
|
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|
5296 <p> |
|
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|
5297 All functions and types from the auxiliary library |
|
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|
5298 are defined in header file <code>lauxlib.h</code> and |
|
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|
5299 have a prefix <code>luaL_</code>. |
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|
5300 |
|
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|
5301 |
|
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|
5302 <p> |
|
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|
5303 All functions in the auxiliary library are built on |
|
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|
5304 top of the basic API, |
|
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|
5305 and so they provide nothing that cannot be done with that API. |
|
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|
5306 Nevertheless, the use of the auxiliary library ensures |
|
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|
5307 more consistency to your code. |
|
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|
5308 |
|
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|
5309 |
|
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|
5310 <p> |
|
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|
5311 Several functions in the auxiliary library use internally some |
|
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|
5312 extra stack slots. |
|
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|
5313 When a function in the auxiliary library uses less than five slots, |
|
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|
5314 it does not check the stack size; |
|
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|
5315 it simply assumes that there are enough slots. |
|
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5316 |
|
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|
5317 |
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|
5318 <p> |
|
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|
5319 Several functions in the auxiliary library are used to |
|
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|
5320 check C function arguments. |
|
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|
5321 Because the error message is formatted for arguments |
|
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|
5322 (e.g., "<code>bad argument #1</code>"), |
|
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|
5323 you should not use these functions for other stack values. |
|
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|
5324 |
|
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|
5325 |
|
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|
5326 <p> |
|
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|
5327 Functions called <code>luaL_check*</code> |
|
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|
5328 always raise an error if the check is not satisfied. |
|
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|
5329 |
|
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|
5330 |
|
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|
5331 |
|
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|
5332 <h2>5.1 – <a name="5.1">Functions and Types</a></h2> |
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|
5333 |
|
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|
5334 <p> |
|
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|
5335 Here we list all functions and types from the auxiliary library |
|
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|
5336 in alphabetical order. |
|
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|
5337 |
|
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|
5338 |
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|
5339 |
|
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|
5340 <hr><h3><a name="luaL_addchar"><code>luaL_addchar</code></a></h3><p> |
|
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|
5341 <span class="apii">[-?, +?, <em>e</em>]</span> |
|
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|
5342 <pre>void luaL_addchar (luaL_Buffer *B, char c);</pre> |
|
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5343 |
|
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|
5344 <p> |
|
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|
5345 Adds the byte <code>c</code> to the buffer <code>B</code> |
|
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|
5346 (see <a href="#luaL_Buffer"><code>luaL_Buffer</code></a>). |
|
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|
5347 |
|
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|
5348 |
|
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|
5349 |
|
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|
5350 |
|
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|
5351 |
|
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|
5352 <hr><h3><a name="luaL_addlstring"><code>luaL_addlstring</code></a></h3><p> |
|
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|
5353 <span class="apii">[-?, +?, <em>e</em>]</span> |
|
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|
5354 <pre>void luaL_addlstring (luaL_Buffer *B, const char *s, size_t l);</pre> |
|
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|
5355 |
|
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|
5356 <p> |
|
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|
5357 Adds the string pointed to by <code>s</code> with length <code>l</code> to |
|
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|
5358 the buffer <code>B</code> |
|
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|
5359 (see <a href="#luaL_Buffer"><code>luaL_Buffer</code></a>). |
|
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|
5360 The string can contain embedded zeros. |
|
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|
5361 |
|
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|
5362 |
|
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|
5363 |
|
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|
5364 |
|
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|
5365 |
|
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|
5366 <hr><h3><a name="luaL_addsize"><code>luaL_addsize</code></a></h3><p> |
|
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|
5367 <span class="apii">[-?, +?, <em>e</em>]</span> |
|
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|
5368 <pre>void luaL_addsize (luaL_Buffer *B, size_t n);</pre> |
|
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|
5369 |
|
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|
5370 <p> |
|
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|
5371 Adds to the buffer <code>B</code> (see <a href="#luaL_Buffer"><code>luaL_Buffer</code></a>) |
|
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|
5372 a string of length <code>n</code> previously copied to the |
|
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|
5373 buffer area (see <a href="#luaL_prepbuffer"><code>luaL_prepbuffer</code></a>). |
|
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|
5374 |
|
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|
5375 |
|
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|
5376 |
|
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|
5377 |
|
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|
5378 |
|
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|
5379 <hr><h3><a name="luaL_addstring"><code>luaL_addstring</code></a></h3><p> |
|
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|
5380 <span class="apii">[-?, +?, <em>e</em>]</span> |
|
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|
5381 <pre>void luaL_addstring (luaL_Buffer *B, const char *s);</pre> |
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|
5382 |
|
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|
5383 <p> |
|
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|
5384 Adds the zero-terminated string pointed to by <code>s</code> |
|
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|
5385 to the buffer <code>B</code> |
|
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|
5386 (see <a href="#luaL_Buffer"><code>luaL_Buffer</code></a>). |
|
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|
5387 |
|
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|
5388 |
|
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|
5389 |
|
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|
5390 |
|
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|
5391 |
|
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|
5392 <hr><h3><a name="luaL_addvalue"><code>luaL_addvalue</code></a></h3><p> |
|
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|
5393 <span class="apii">[-1, +?, <em>e</em>]</span> |
|
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|
5394 <pre>void luaL_addvalue (luaL_Buffer *B);</pre> |
|
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5395 |
|
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|
5396 <p> |
|
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|
5397 Adds the value at the top of the stack |
|
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|
5398 to the buffer <code>B</code> |
|
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changeset
|
5399 (see <a href="#luaL_Buffer"><code>luaL_Buffer</code></a>). |
|
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|
5400 Pops the value. |
|
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changeset
|
5401 |
|
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|
5402 |
|
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|
5403 <p> |
|
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|
5404 This is the only function on string buffers that can (and must) |
|
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|
5405 be called with an extra element on the stack, |
|
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|
5406 which is the value to be added to the buffer. |
|
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|
5407 |
|
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changeset
|
5408 |
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|
5409 |
|
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changeset
|
5410 |
|
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diff
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|
5411 |
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|
5412 <hr><h3><a name="luaL_argcheck"><code>luaL_argcheck</code></a></h3><p> |
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5413 <span class="apii">[-0, +0, <em>v</em>]</span> |
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|
5414 <pre>void luaL_argcheck (lua_State *L, |
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5415 int cond, |
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|
5416 int arg, |
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|
5417 const char *extramsg);</pre> |
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5418 |
|
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|
5419 <p> |
|
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|
5420 Checks whether <code>cond</code> is true. |
|
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|
5421 If it is not, raises an error with a standard message (see <a href="#luaL_argerror"><code>luaL_argerror</code></a>). |
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|
5422 |
|
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|
5423 |
|
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diff
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|
5424 |
|
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|
5425 |
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|
5426 |
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|
5427 <hr><h3><a name="luaL_argerror"><code>luaL_argerror</code></a></h3><p> |
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5428 <span class="apii">[-0, +0, <em>v</em>]</span> |
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|
5429 <pre>int luaL_argerror (lua_State *L, int arg, const char *extramsg);</pre> |
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|
5430 |
|
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|
5431 <p> |
|
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|
5432 Raises an error reporting a problem with argument <code>arg</code> |
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|
5433 of the C function that called it, |
|
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|
5434 using a standard message |
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|
5435 that includes <code>extramsg</code> as a comment: |
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5436 |
|
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|
5437 <pre> |
|
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|
5438 bad argument #<em>arg</em> to '<em>funcname</em>' (<em>extramsg</em>) |
|
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|
5439 </pre><p> |
|
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|
5440 This function never returns. |
|
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|
5441 |
|
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|
5442 |
|
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|
5443 |
|
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|
5444 |
|
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|
5445 |
|
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|
5446 <hr><h3><a name="luaL_Buffer"><code>luaL_Buffer</code></a></h3> |
|
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|
5447 <pre>typedef struct luaL_Buffer luaL_Buffer;</pre> |
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|
5448 |
|
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|
5449 <p> |
|
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|
5450 Type for a <em>string buffer</em>. |
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|
5451 |
|
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|
5452 |
|
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|
5453 <p> |
|
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|
5454 A string buffer allows C code to build Lua strings piecemeal. |
|
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|
5455 Its pattern of use is as follows: |
|
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5456 |
|
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|
5457 <ul> |
|
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5458 |
|
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|
5459 <li>First declare a variable <code>b</code> of type <a href="#luaL_Buffer"><code>luaL_Buffer</code></a>.</li> |
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|
5460 |
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|
5461 <li>Then initialize it with a call <code>luaL_buffinit(L, &b)</code>.</li> |
|
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5462 |
|
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|
5463 <li> |
|
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|
5464 Then add string pieces to the buffer calling any of |
|
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|
5465 the <code>luaL_add*</code> functions. |
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|
5466 </li> |
|
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|
5467 |
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|
5468 <li> |
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|
5469 Finish by calling <code>luaL_pushresult(&b)</code>. |
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|
5470 This call leaves the final string on the top of the stack. |
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|
5471 </li> |
|
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|
5472 |
|
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|
5473 </ul> |
|
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|
5474 |
|
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|
5475 <p> |
|
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|
5476 If you know beforehand the total size of the resulting string, |
|
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|
5477 you can use the buffer like this: |
|
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|
5478 |
|
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|
5479 <ul> |
|
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|
5480 |
|
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|
5481 <li>First declare a variable <code>b</code> of type <a href="#luaL_Buffer"><code>luaL_Buffer</code></a>.</li> |
|
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|
5482 |
|
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|
5483 <li>Then initialize it and preallocate a space of |
|
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|
5484 size <code>sz</code> with a call <code>luaL_buffinitsize(L, &b, sz)</code>.</li> |
|
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|
5485 |
|
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|
5486 <li>Then copy the string into that space.</li> |
|
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|
5487 |
|
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|
5488 <li> |
|
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|
5489 Finish by calling <code>luaL_pushresultsize(&b, sz)</code>, |
|
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|
5490 where <code>sz</code> is the total size of the resulting string |
|
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|
5491 copied into that space. |
|
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|
5492 </li> |
|
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|
5493 |
|
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|
5494 </ul> |
|
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|
5495 |
|
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|
5496 <p> |
|
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|
5497 During its normal operation, |
|
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|
5498 a string buffer uses a variable number of stack slots. |
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|
5499 So, while using a buffer, you cannot assume that you know where |
|
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|
5500 the top of the stack is. |
|
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|
5501 You can use the stack between successive calls to buffer operations |
|
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|
5502 as long as that use is balanced; |
|
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|
5503 that is, |
|
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|
5504 when you call a buffer operation, |
|
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|
5505 the stack is at the same level |
|
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|
5506 it was immediately after the previous buffer operation. |
|
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|
5507 (The only exception to this rule is <a href="#luaL_addvalue"><code>luaL_addvalue</code></a>.) |
|
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|
5508 After calling <a href="#luaL_pushresult"><code>luaL_pushresult</code></a> the stack is back to its |
|
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|
5509 level when the buffer was initialized, |
|
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|
5510 plus the final string on its top. |
|
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|
5511 |
|
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|
5512 |
|
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|
5513 |
|
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|
5514 |
|
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|
5515 |
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|
5516 <hr><h3><a name="luaL_buffinit"><code>luaL_buffinit</code></a></h3><p> |
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5517 <span class="apii">[-0, +0, –]</span> |
|
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|
5518 <pre>void luaL_buffinit (lua_State *L, luaL_Buffer *B);</pre> |
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5519 |
|
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|
5520 <p> |
|
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|
5521 Initializes a buffer <code>B</code>. |
|
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|
5522 This function does not allocate any space; |
|
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|
5523 the buffer must be declared as a variable |
|
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|
5524 (see <a href="#luaL_Buffer"><code>luaL_Buffer</code></a>). |
|
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|
5525 |
|
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diff
changeset
|
5526 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
5527 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
5528 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
5529 |
|
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|
5530 <hr><h3><a name="luaL_buffinitsize"><code>luaL_buffinitsize</code></a></h3><p> |
|
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|
5531 <span class="apii">[-?, +?, <em>e</em>]</span> |
|
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|
5532 <pre>char *luaL_buffinitsize (lua_State *L, luaL_Buffer *B, size_t sz);</pre> |
|
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|
5533 |
|
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diff
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|
5534 <p> |
|
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|
5535 Equivalent to the sequence |
|
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add manual.html as copy of Lua 5.3 Reference Manual
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diff
changeset
|
5536 <a href="#luaL_buffinit"><code>luaL_buffinit</code></a>, <a href="#luaL_prepbuffsize"><code>luaL_prepbuffsize</code></a>. |
|
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diff
changeset
|
5537 |
|
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parents:
diff
changeset
|
5538 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
5539 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
5540 |
|
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Franklin Schmidt <fschmidt@gmail.com>
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diff
changeset
|
5541 |
|
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|
5542 <hr><h3><a name="luaL_callmeta"><code>luaL_callmeta</code></a></h3><p> |
|
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|
5543 <span class="apii">[-0, +(0|1), <em>e</em>]</span> |
|
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|
5544 <pre>int luaL_callmeta (lua_State *L, int obj, const char *e);</pre> |
|
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|
5545 |
|
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|
5546 <p> |
|
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|
5547 Calls a metamethod. |
|
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|
5548 |
|
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diff
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|
5549 |
|
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|
5550 <p> |
|
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|
5551 If the object at index <code>obj</code> has a metatable and this |
|
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|
5552 metatable has a field <code>e</code>, |
|
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|
5553 this function calls this field passing the object as its only argument. |
|
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|
5554 In this case this function returns true and pushes onto the |
|
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|
5555 stack the value returned by the call. |
|
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diff
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|
5556 If there is no metatable or no metamethod, |
|
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|
5557 this function returns false (without pushing any value on the stack). |
|
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diff
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|
5558 |
|
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diff
changeset
|
5559 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
5560 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
5561 |
|
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Franklin Schmidt <fschmidt@gmail.com>
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diff
changeset
|
5562 |
|
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|
5563 <hr><h3><a name="luaL_checkany"><code>luaL_checkany</code></a></h3><p> |
|
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|
5564 <span class="apii">[-0, +0, <em>v</em>]</span> |
|
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|
5565 <pre>void luaL_checkany (lua_State *L, int arg);</pre> |
|
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|
5566 |
|
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diff
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|
5567 <p> |
|
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|
5568 Checks whether the function has an argument |
|
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diff
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|
5569 of any type (including <b>nil</b>) at position <code>arg</code>. |
|
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|
5570 |
|
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diff
changeset
|
5571 |
|
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parents:
diff
changeset
|
5572 |
|
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diff
changeset
|
5573 |
|
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Franklin Schmidt <fschmidt@gmail.com>
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diff
changeset
|
5574 |
|
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|
5575 <hr><h3><a name="luaL_checkinteger"><code>luaL_checkinteger</code></a></h3><p> |
|
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|
5576 <span class="apii">[-0, +0, <em>v</em>]</span> |
|
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|
5577 <pre>lua_Integer luaL_checkinteger (lua_State *L, int arg);</pre> |
|
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|
5578 |
|
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|
5579 <p> |
|
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|
5580 Checks whether the function argument <code>arg</code> is an integer |
|
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|
5581 (or can be converted to an integer) |
|
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|
5582 and returns this integer cast to a <a href="#lua_Integer"><code>lua_Integer</code></a>. |
|
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|
5583 |
|
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parents:
diff
changeset
|
5584 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
5585 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
5586 |
|
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Franklin Schmidt <fschmidt@gmail.com>
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diff
changeset
|
5587 |
|
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|
5588 <hr><h3><a name="luaL_checklstring"><code>luaL_checklstring</code></a></h3><p> |
|
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|
5589 <span class="apii">[-0, +0, <em>v</em>]</span> |
|
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|
5590 <pre>const char *luaL_checklstring (lua_State *L, int arg, size_t *l);</pre> |
|
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|
5591 |
|
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diff
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|
5592 <p> |
|
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diff
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|
5593 Checks whether the function argument <code>arg</code> is a string |
|
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|
5594 and returns this string; |
|
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diff
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|
5595 if <code>l</code> is not <code>NULL</code> fills <code>*l</code> |
|
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diff
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|
5596 with the string's length. |
|
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diff
changeset
|
5597 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
5598 |
|
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diff
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|
5599 <p> |
|
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diff
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|
5600 This function uses <a href="#lua_tolstring"><code>lua_tolstring</code></a> to get its result, |
|
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parents:
diff
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|
5601 so all conversions and caveats of that function apply here. |
|
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parents:
diff
changeset
|
5602 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
5603 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
5604 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
5605 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
5606 |
|
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|
5607 <hr><h3><a name="luaL_checknumber"><code>luaL_checknumber</code></a></h3><p> |
|
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|
5608 <span class="apii">[-0, +0, <em>v</em>]</span> |
|
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|
5609 <pre>lua_Number luaL_checknumber (lua_State *L, int arg);</pre> |
|
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changeset
|
5610 |
|
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diff
changeset
|
5611 <p> |
|
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diff
changeset
|
5612 Checks whether the function argument <code>arg</code> is a number |
|
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|
5613 and returns this number. |
|
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diff
changeset
|
5614 |
|
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changeset
|
5615 |
|
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diff
changeset
|
5616 |
|
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changeset
|
5617 |
|
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changeset
|
5618 |
|
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|
5619 <hr><h3><a name="luaL_checkoption"><code>luaL_checkoption</code></a></h3><p> |
|
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|
5620 <span class="apii">[-0, +0, <em>v</em>]</span> |
|
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|
5621 <pre>int luaL_checkoption (lua_State *L, |
|
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|
5622 int arg, |
|
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|
5623 const char *def, |
|
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|
5624 const char *const lst[]);</pre> |
|
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|
5625 |
|
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changeset
|
5626 <p> |
|
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changeset
|
5627 Checks whether the function argument <code>arg</code> is a string and |
|
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changeset
|
5628 searches for this string in the array <code>lst</code> |
|
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|
5629 (which must be NULL-terminated). |
|
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|
5630 Returns the index in the array where the string was found. |
|
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|
5631 Raises an error if the argument is not a string or |
|
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|
5632 if the string cannot be found. |
|
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diff
changeset
|
5633 |
|
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diff
changeset
|
5634 |
|
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changeset
|
5635 <p> |
|
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diff
changeset
|
5636 If <code>def</code> is not <code>NULL</code>, |
|
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changeset
|
5637 the function uses <code>def</code> as a default value when |
|
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diff
changeset
|
5638 there is no argument <code>arg</code> or when this argument is <b>nil</b>. |
|
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changeset
|
5639 |
|
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diff
changeset
|
5640 |
|
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|
5641 <p> |
|
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changeset
|
5642 This is a useful function for mapping strings to C enums. |
|
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|
5643 (The usual convention in Lua libraries is |
|
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|
5644 to use strings instead of numbers to select options.) |
|
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|
5645 |
|
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|
5646 |
|
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|
5647 |
|
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|
5648 |
|
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diff
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|
5649 |
|
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|
5650 <hr><h3><a name="luaL_checkstack"><code>luaL_checkstack</code></a></h3><p> |
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|
5651 <span class="apii">[-0, +0, <em>v</em>]</span> |
|
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|
5652 <pre>void luaL_checkstack (lua_State *L, int sz, const char *msg);</pre> |
|
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|
5653 |
|
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|
5654 <p> |
|
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|
5655 Grows the stack size to <code>top + sz</code> elements, |
|
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|
5656 raising an error if the stack cannot grow to that size. |
|
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|
5657 <code>msg</code> is an additional text to go into the error message |
|
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|
5658 (or <code>NULL</code> for no additional text). |
|
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|
5659 |
|
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|
5660 |
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|
5661 |
|
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|
5662 |
|
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|
5663 |
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|
5664 <hr><h3><a name="luaL_checkstring"><code>luaL_checkstring</code></a></h3><p> |
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|
5665 <span class="apii">[-0, +0, <em>v</em>]</span> |
|
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|
5666 <pre>const char *luaL_checkstring (lua_State *L, int arg);</pre> |
|
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|
5667 |
|
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|
5668 <p> |
|
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|
5669 Checks whether the function argument <code>arg</code> is a string |
|
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|
5670 and returns this string. |
|
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|
5671 |
|
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|
5672 |
|
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|
5673 <p> |
|
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|
5674 This function uses <a href="#lua_tolstring"><code>lua_tolstring</code></a> to get its result, |
|
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|
5675 so all conversions and caveats of that function apply here. |
|
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|
5676 |
|
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|
5677 |
|
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|
5678 |
|
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diff
changeset
|
5679 |
|
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diff
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|
5680 |
|
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|
5681 <hr><h3><a name="luaL_checktype"><code>luaL_checktype</code></a></h3><p> |
|
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|
5682 <span class="apii">[-0, +0, <em>v</em>]</span> |
|
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|
5683 <pre>void luaL_checktype (lua_State *L, int arg, int t);</pre> |
|
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|
5684 |
|
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|
5685 <p> |
|
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|
5686 Checks whether the function argument <code>arg</code> has type <code>t</code>. |
|
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|
5687 See <a href="#lua_type"><code>lua_type</code></a> for the encoding of types for <code>t</code>. |
|
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|
5688 |
|
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diff
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|
5689 |
|
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parents:
diff
changeset
|
5690 |
|
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Franklin Schmidt <fschmidt@gmail.com>
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diff
changeset
|
5691 |
|
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Franklin Schmidt <fschmidt@gmail.com>
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diff
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|
5692 |
|
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|
5693 <hr><h3><a name="luaL_checkudata"><code>luaL_checkudata</code></a></h3><p> |
|
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|
5694 <span class="apii">[-0, +0, <em>v</em>]</span> |
|
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|
5695 <pre>void *luaL_checkudata (lua_State *L, int arg, const char *tname);</pre> |
|
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|
5696 |
|
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|
5697 <p> |
|
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|
5698 Checks whether the function argument <code>arg</code> is a userdata |
|
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|
5699 of the type <code>tname</code> (see <a href="#luaL_newmetatable"><code>luaL_newmetatable</code></a>) and |
|
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|
5700 returns the userdata address (see <a href="#lua_touserdata"><code>lua_touserdata</code></a>). |
|
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|
5701 |
|
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diff
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|
5702 |
|
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diff
changeset
|
5703 |
|
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diff
changeset
|
5704 |
|
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diff
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|
5705 |
|
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|
5706 <hr><h3><a name="luaL_checkversion"><code>luaL_checkversion</code></a></h3><p> |
|
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|
5707 <span class="apii">[-0, +0, –]</span> |
|
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|
5708 <pre>void luaL_checkversion (lua_State *L);</pre> |
|
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|
5709 |
|
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|
5710 <p> |
|
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|
5711 Checks whether the core running the call, |
|
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|
5712 the core that created the Lua state, |
|
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|
5713 and the code making the call are all using the same version of Lua. |
|
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|
5714 Also checks whether the core running the call |
|
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changeset
|
5715 and the core that created the Lua state |
|
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changeset
|
5716 are using the same address space. |
|
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diff
changeset
|
5717 |
|
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diff
changeset
|
5718 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
5719 |
|
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parents:
diff
changeset
|
5720 |
|
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diff
changeset
|
5721 |
|
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|
5722 <hr><h3><a name="luaL_dofile"><code>luaL_dofile</code></a></h3><p> |
|
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|
5723 <span class="apii">[-0, +?, <em>e</em>]</span> |
|
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|
5724 <pre>int luaL_dofile (lua_State *L, const char *filename);</pre> |
|
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|
5725 |
|
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|
5726 <p> |
|
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changeset
|
5727 Loads and runs the given file. |
|
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|
5728 It is defined as the following macro: |
|
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|
5729 |
|
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|
5730 <pre> |
|
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changeset
|
5731 (luaL_loadfile(L, filename) || lua_pcall(L, 0, LUA_MULTRET, 0)) |
|
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|
5732 </pre><p> |
|
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|
5733 It returns false if there are no errors |
|
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changeset
|
5734 or true in case of errors. |
|
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changeset
|
5735 |
|
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changeset
|
5736 |
|
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changeset
|
5737 |
|
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changeset
|
5738 |
|
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changeset
|
5739 |
|
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|
5740 <hr><h3><a name="luaL_dostring"><code>luaL_dostring</code></a></h3><p> |
|
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|
5741 <span class="apii">[-0, +?, –]</span> |
|
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|
5742 <pre>int luaL_dostring (lua_State *L, const char *str);</pre> |
|
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|
5743 |
|
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|
5744 <p> |
|
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changeset
|
5745 Loads and runs the given string. |
|
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changeset
|
5746 It is defined as the following macro: |
|
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changeset
|
5747 |
|
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|
5748 <pre> |
|
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|
5749 (luaL_loadstring(L, str) || lua_pcall(L, 0, LUA_MULTRET, 0)) |
|
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|
5750 </pre><p> |
|
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|
5751 It returns false if there are no errors |
|
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changeset
|
5752 or true in case of errors. |
|
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changeset
|
5753 |
|
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diff
changeset
|
5754 |
|
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changeset
|
5755 |
|
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diff
changeset
|
5756 |
|
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diff
changeset
|
5757 |
|
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changeset
|
5758 <hr><h3><a name="luaL_error"><code>luaL_error</code></a></h3><p> |
|
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5759 <span class="apii">[-0, +0, <em>v</em>]</span> |
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|
5760 <pre>int luaL_error (lua_State *L, const char *fmt, ...);</pre> |
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5761 |
|
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|
5762 <p> |
|
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|
5763 Raises an error. |
|
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|
5764 The error message format is given by <code>fmt</code> |
|
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|
5765 plus any extra arguments, |
|
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|
5766 following the same rules of <a href="#lua_pushfstring"><code>lua_pushfstring</code></a>. |
|
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|
5767 It also adds at the beginning of the message the file name and |
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|
5768 the line number where the error occurred, |
|
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|
5769 if this information is available. |
|
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|
5770 |
|
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|
5771 |
|
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|
5772 <p> |
|
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|
5773 This function never returns, |
|
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|
5774 but it is an idiom to use it in C functions |
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|
5775 as <code>return luaL_error(<em>args</em>)</code>. |
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5776 |
|
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|
5777 |
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|
5778 |
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|
5779 |
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|
5780 |
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|
5781 <hr><h3><a name="luaL_execresult"><code>luaL_execresult</code></a></h3><p> |
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|
5782 <span class="apii">[-0, +3, <em>e</em>]</span> |
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|
5783 <pre>int luaL_execresult (lua_State *L, int stat);</pre> |
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|
5784 |
|
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|
5785 <p> |
|
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|
5786 This function produces the return values for |
|
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|
5787 process-related functions in the standard library |
|
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|
5788 (<a href="#pdf-os.execute"><code>os.execute</code></a> and <a href="#pdf-io.close"><code>io.close</code></a>). |
|
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|
5789 |
|
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|
5790 |
|
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|
5791 |
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|
5792 |
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|
5793 |
|
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|
5794 <hr><h3><a name="luaL_fileresult"><code>luaL_fileresult</code></a></h3><p> |
|
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|
5795 <span class="apii">[-0, +(1|3), <em>e</em>]</span> |
|
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|
5796 <pre>int luaL_fileresult (lua_State *L, int stat, const char *fname);</pre> |
|
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|
5797 |
|
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|
5798 <p> |
|
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|
5799 This function produces the return values for |
|
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|
5800 file-related functions in the standard library |
|
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|
5801 (<a href="#pdf-io.open"><code>io.open</code></a>, <a href="#pdf-os.rename"><code>os.rename</code></a>, <a href="#pdf-file:seek"><code>file:seek</code></a>, etc.). |
|
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|
5802 |
|
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|
5803 |
|
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|
5804 |
|
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|
5805 |
|
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Franklin Schmidt <fschmidt@gmail.com>
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|
5806 |
|
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|
5807 <hr><h3><a name="luaL_getmetafield"><code>luaL_getmetafield</code></a></h3><p> |
|
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|
5808 <span class="apii">[-0, +(0|1), <em>e</em>]</span> |
|
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|
5809 <pre>int luaL_getmetafield (lua_State *L, int obj, const char *e);</pre> |
|
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|
5810 |
|
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|
5811 <p> |
|
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|
5812 Pushes onto the stack the field <code>e</code> from the metatable |
|
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|
5813 of the object at index <code>obj</code> and returns the type of pushed value. |
|
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|
5814 If the object does not have a metatable, |
|
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|
5815 or if the metatable does not have this field, |
|
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|
5816 pushes nothing and returns <code>LUA_TNIL</code>. |
|
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|
5817 |
|
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|
5818 |
|
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|
5819 |
|
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|
5820 |
|
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|
5821 |
|
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|
5822 <hr><h3><a name="luaL_getmetatable"><code>luaL_getmetatable</code></a></h3><p> |
|
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|
5823 <span class="apii">[-0, +1, –]</span> |
|
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|
5824 <pre>int luaL_getmetatable (lua_State *L, const char *tname);</pre> |
|
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|
5825 |
|
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|
5826 <p> |
|
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|
5827 Pushes onto the stack the metatable associated with name <code>tname</code> |
|
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|
5828 in the registry (see <a href="#luaL_newmetatable"><code>luaL_newmetatable</code></a>). |
|
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|
5829 If there is no metatable associated with <code>tname</code>, |
|
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|
5830 returns false and pushes <b>nil</b>. |
|
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|
5831 |
|
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changeset
|
5832 |
|
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diff
changeset
|
5833 |
|
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changeset
|
5834 |
|
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|
5835 |
|
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|
5836 <hr><h3><a name="luaL_getsubtable"><code>luaL_getsubtable</code></a></h3><p> |
|
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|
5837 <span class="apii">[-0, +1, <em>e</em>]</span> |
|
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|
5838 <pre>int luaL_getsubtable (lua_State *L, int idx, const char *fname);</pre> |
|
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|
5839 |
|
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|
5840 <p> |
|
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|
5841 Ensures that the value <code>t[fname]</code>, |
|
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|
5842 where <code>t</code> is the value at index <code>idx</code>, |
|
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|
5843 is a table, |
|
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|
5844 and pushes that table onto the stack. |
|
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|
5845 Returns true if it finds a previous table there |
|
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|
5846 and false if it creates a new table. |
|
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|
5847 |
|
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|
5848 |
|
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changeset
|
5849 |
|
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|
5850 |
|
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changeset
|
5851 |
|
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|
5852 <hr><h3><a name="luaL_gsub"><code>luaL_gsub</code></a></h3><p> |
|
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|
5853 <span class="apii">[-0, +1, <em>e</em>]</span> |
|
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|
5854 <pre>const char *luaL_gsub (lua_State *L, |
|
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|
5855 const char *s, |
|
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|
5856 const char *p, |
|
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|
5857 const char *r);</pre> |
|
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|
5858 |
|
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|
5859 <p> |
|
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|
5860 Creates a copy of string <code>s</code> by replacing |
|
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|
5861 any occurrence of the string <code>p</code> |
|
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|
5862 with the string <code>r</code>. |
|
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|
5863 Pushes the resulting string on the stack and returns it. |
|
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|
5864 |
|
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changeset
|
5865 |
|
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changeset
|
5866 |
|
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changeset
|
5867 |
|
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|
5868 |
|
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|
5869 <hr><h3><a name="luaL_len"><code>luaL_len</code></a></h3><p> |
|
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|
5870 <span class="apii">[-0, +0, <em>e</em>]</span> |
|
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|
5871 <pre>lua_Integer luaL_len (lua_State *L, int index);</pre> |
|
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|
5872 |
|
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diff
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|
5873 <p> |
|
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diff
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|
5874 Returns the "length" of the value at the given index |
|
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|
5875 as a number; |
|
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add manual.html as copy of Lua 5.3 Reference Manual
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diff
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|
5876 it is equivalent to the '<code>#</code>' operator in Lua (see <a href="#3.4.7">§3.4.7</a>). |
|
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add manual.html as copy of Lua 5.3 Reference Manual
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|
5877 Raises an error if the result of the operation is not an integer. |
|
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add manual.html as copy of Lua 5.3 Reference Manual
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diff
changeset
|
5878 (This case only can happen through metamethods.) |
|
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diff
changeset
|
5879 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
5880 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
5881 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
5882 |
|
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Franklin Schmidt <fschmidt@gmail.com>
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diff
changeset
|
5883 |
|
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|
5884 <hr><h3><a name="luaL_loadbuffer"><code>luaL_loadbuffer</code></a></h3><p> |
|
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|
5885 <span class="apii">[-0, +1, –]</span> |
|
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|
5886 <pre>int luaL_loadbuffer (lua_State *L, |
|
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|
5887 const char *buff, |
|
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|
5888 size_t sz, |
|
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add manual.html as copy of Lua 5.3 Reference Manual
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diff
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|
5889 const char *name);</pre> |
|
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|
5890 |
|
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diff
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|
5891 <p> |
|
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diff
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|
5892 Equivalent to <a href="#luaL_loadbufferx"><code>luaL_loadbufferx</code></a> with <code>mode</code> equal to <code>NULL</code>. |
|
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|
5893 |
|
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Franklin Schmidt <fschmidt@gmail.com>
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diff
changeset
|
5894 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
5895 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
5896 |
|
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Franklin Schmidt <fschmidt@gmail.com>
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diff
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|
5897 |
|
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|
5898 <hr><h3><a name="luaL_loadbufferx"><code>luaL_loadbufferx</code></a></h3><p> |
|
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|
5899 <span class="apii">[-0, +1, –]</span> |
|
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|
5900 <pre>int luaL_loadbufferx (lua_State *L, |
|
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|
5901 const char *buff, |
|
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|
5902 size_t sz, |
|
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|
5903 const char *name, |
|
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|
5904 const char *mode);</pre> |
|
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|
5905 |
|
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Franklin Schmidt <fschmidt@gmail.com>
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diff
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|
5906 <p> |
|
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diff
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|
5907 Loads a buffer as a Lua chunk. |
|
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diff
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|
5908 This function uses <a href="#lua_load"><code>lua_load</code></a> to load the chunk in the |
|
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|
5909 buffer pointed to by <code>buff</code> with size <code>sz</code>. |
|
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|
5910 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
5911 |
|
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|
5912 <p> |
|
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|
5913 This function returns the same results as <a href="#lua_load"><code>lua_load</code></a>. |
|
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|
5914 <code>name</code> is the chunk name, |
|
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|
5915 used for debug information and error messages. |
|
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|
5916 The string <code>mode</code> works as in function <a href="#lua_load"><code>lua_load</code></a>. |
|
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|
5917 |
|
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parents:
diff
changeset
|
5918 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
5919 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
5920 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
5921 |
|
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|
5922 <hr><h3><a name="luaL_loadfile"><code>luaL_loadfile</code></a></h3><p> |
|
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|
5923 <span class="apii">[-0, +1, <em>e</em>]</span> |
|
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|
5924 <pre>int luaL_loadfile (lua_State *L, const char *filename);</pre> |
|
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|
5925 |
|
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|
5926 <p> |
|
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|
5927 Equivalent to <a href="#luaL_loadfilex"><code>luaL_loadfilex</code></a> with <code>mode</code> equal to <code>NULL</code>. |
|
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changeset
|
5928 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
5929 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
5930 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
5931 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
5932 |
|
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|
5933 <hr><h3><a name="luaL_loadfilex"><code>luaL_loadfilex</code></a></h3><p> |
|
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|
5934 <span class="apii">[-0, +1, <em>e</em>]</span> |
|
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|
5935 <pre>int luaL_loadfilex (lua_State *L, const char *filename, |
|
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|
5936 const char *mode);</pre> |
|
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|
5937 |
|
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diff
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|
5938 <p> |
|
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diff
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|
5939 Loads a file as a Lua chunk. |
|
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|
5940 This function uses <a href="#lua_load"><code>lua_load</code></a> to load the chunk in the file |
|
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|
5941 named <code>filename</code>. |
|
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diff
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|
5942 If <code>filename</code> is <code>NULL</code>, |
|
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|
5943 then it loads from the standard input. |
|
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diff
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|
5944 The first line in the file is ignored if it starts with a <code>#</code>. |
|
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diff
changeset
|
5945 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
5946 |
|
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diff
changeset
|
5947 <p> |
|
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diff
changeset
|
5948 The string <code>mode</code> works as in function <a href="#lua_load"><code>lua_load</code></a>. |
|
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diff
changeset
|
5949 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
5950 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
5951 <p> |
|
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diff
changeset
|
5952 This function returns the same results as <a href="#lua_load"><code>lua_load</code></a>, |
|
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|
5953 but it has an extra error code <a name="pdf-LUA_ERRFILE"><code>LUA_ERRFILE</code></a> |
|
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diff
changeset
|
5954 if it cannot open/read the file or the file has a wrong mode. |
|
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diff
changeset
|
5955 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
5956 |
|
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diff
changeset
|
5957 <p> |
|
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changeset
|
5958 As <a href="#lua_load"><code>lua_load</code></a>, this function only loads the chunk; |
|
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changeset
|
5959 it does not run it. |
|
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diff
changeset
|
5960 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
5961 |
|
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diff
changeset
|
5962 |
|
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diff
changeset
|
5963 |
|
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diff
changeset
|
5964 |
|
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|
5965 <hr><h3><a name="luaL_loadstring"><code>luaL_loadstring</code></a></h3><p> |
|
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|
5966 <span class="apii">[-0, +1, –]</span> |
|
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|
5967 <pre>int luaL_loadstring (lua_State *L, const char *s);</pre> |
|
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changeset
|
5968 |
|
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changeset
|
5969 <p> |
|
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changeset
|
5970 Loads a string as a Lua chunk. |
|
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changeset
|
5971 This function uses <a href="#lua_load"><code>lua_load</code></a> to load the chunk in |
|
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|
5972 the zero-terminated string <code>s</code>. |
|
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changeset
|
5973 |
|
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diff
changeset
|
5974 |
|
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changeset
|
5975 <p> |
|
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changeset
|
5976 This function returns the same results as <a href="#lua_load"><code>lua_load</code></a>. |
|
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changeset
|
5977 |
|
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diff
changeset
|
5978 |
|
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changeset
|
5979 <p> |
|
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changeset
|
5980 Also as <a href="#lua_load"><code>lua_load</code></a>, this function only loads the chunk; |
|
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changeset
|
5981 it does not run it. |
|
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diff
changeset
|
5982 |
|
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diff
changeset
|
5983 |
|
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diff
changeset
|
5984 |
|
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diff
changeset
|
5985 |
|
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diff
changeset
|
5986 |
|
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changeset
|
5987 <hr><h3><a name="luaL_newlib"><code>luaL_newlib</code></a></h3><p> |
|
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changeset
|
5988 <span class="apii">[-0, +1, <em>e</em>]</span> |
|
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|
5989 <pre>void luaL_newlib (lua_State *L, const luaL_Reg l[]);</pre> |
|
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|
5990 |
|
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|
5991 <p> |
|
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|
5992 Creates a new table and registers there |
|
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|
5993 the functions in list <code>l</code>. |
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|
5994 |
|
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|
5995 |
|
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|
5996 <p> |
|
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|
5997 It is implemented as the following macro: |
|
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|
5998 |
|
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|
5999 <pre> |
|
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|
6000 (luaL_newlibtable(L,l), luaL_setfuncs(L,l,0)) |
|
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|
6001 </pre><p> |
|
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|
6002 The array <code>l</code> must be the actual array, |
|
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6003 not a pointer to it. |
|
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|
6004 |
|
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|
6005 |
|
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|
6006 |
|
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|
6007 |
|
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|
6008 |
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|
6009 <hr><h3><a name="luaL_newlibtable"><code>luaL_newlibtable</code></a></h3><p> |
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|
6010 <span class="apii">[-0, +1, <em>e</em>]</span> |
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|
6011 <pre>void luaL_newlibtable (lua_State *L, const luaL_Reg l[]);</pre> |
|
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|
6012 |
|
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|
6013 <p> |
|
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|
6014 Creates a new table with a size optimized |
|
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|
6015 to store all entries in the array <code>l</code> |
|
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|
6016 (but does not actually store them). |
|
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|
6017 It is intended to be used in conjunction with <a href="#luaL_setfuncs"><code>luaL_setfuncs</code></a> |
|
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|
6018 (see <a href="#luaL_newlib"><code>luaL_newlib</code></a>). |
|
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|
6019 |
|
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|
6020 |
|
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|
6021 <p> |
|
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|
6022 It is implemented as a macro. |
|
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|
6023 The array <code>l</code> must be the actual array, |
|
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|
6024 not a pointer to it. |
|
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|
6025 |
|
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changeset
|
6026 |
|
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diff
changeset
|
6027 |
|
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changeset
|
6028 |
|
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diff
changeset
|
6029 |
|
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|
6030 <hr><h3><a name="luaL_newmetatable"><code>luaL_newmetatable</code></a></h3><p> |
|
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|
6031 <span class="apii">[-0, +1, <em>e</em>]</span> |
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|
6032 <pre>int luaL_newmetatable (lua_State *L, const char *tname);</pre> |
|
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|
6033 |
|
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|
6034 <p> |
|
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|
6035 If the registry already has the key <code>tname</code>, |
|
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|
6036 returns 0. |
|
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|
6037 Otherwise, |
|
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|
6038 creates a new table to be used as a metatable for userdata, |
|
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|
6039 adds to this new table the pair <code>__name = tname</code>, |
|
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|
6040 adds to the registry the pair <code>[tname] = new table</code>, |
|
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|
6041 and returns 1. |
|
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|
6042 (The entry <code>__name</code> is used by some error-reporting functions.) |
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|
6043 |
|
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|
6044 |
|
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|
6045 <p> |
|
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|
6046 In both cases pushes onto the stack the final value associated |
|
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|
6047 with <code>tname</code> in the registry. |
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|
6048 |
|
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|
6049 |
|
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|
6050 |
|
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|
6051 |
|
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|
6052 |
|
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|
6053 <hr><h3><a name="luaL_newstate"><code>luaL_newstate</code></a></h3><p> |
|
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|
6054 <span class="apii">[-0, +0, –]</span> |
|
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|
6055 <pre>lua_State *luaL_newstate (void);</pre> |
|
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|
6056 |
|
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|
6057 <p> |
|
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|
6058 Creates a new Lua state. |
|
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|
6059 It calls <a href="#lua_newstate"><code>lua_newstate</code></a> with an |
|
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|
6060 allocator based on the standard C <code>realloc</code> function |
|
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|
6061 and then sets a panic function (see <a href="#4.6">§4.6</a>) that prints |
|
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|
6062 an error message to the standard error output in case of fatal |
|
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|
6063 errors. |
|
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changeset
|
6064 |
|
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|
6065 |
|
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|
6066 <p> |
|
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|
6067 Returns the new state, |
|
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|
6068 or <code>NULL</code> if there is a memory allocation error. |
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|
6069 |
|
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changeset
|
6070 |
|
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changeset
|
6071 |
|
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changeset
|
6072 |
|
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|
6073 |
|
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|
6074 <hr><h3><a name="luaL_openlibs"><code>luaL_openlibs</code></a></h3><p> |
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|
6075 <span class="apii">[-0, +0, <em>e</em>]</span> |
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|
6076 <pre>void luaL_openlibs (lua_State *L);</pre> |
|
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|
6077 |
|
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|
6078 <p> |
|
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|
6079 Opens all standard Lua libraries into the given state. |
|
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changeset
|
6080 |
|
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changeset
|
6081 |
|
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changeset
|
6082 |
|
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changeset
|
6083 |
|
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changeset
|
6084 |
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|
6085 <hr><h3><a name="luaL_optinteger"><code>luaL_optinteger</code></a></h3><p> |
|
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|
6086 <span class="apii">[-0, +0, <em>v</em>]</span> |
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|
6087 <pre>lua_Integer luaL_optinteger (lua_State *L, |
|
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|
6088 int arg, |
|
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|
6089 lua_Integer d);</pre> |
|
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|
6090 |
|
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changeset
|
6091 <p> |
|
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|
6092 If the function argument <code>arg</code> is an integer |
|
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|
6093 (or convertible to an integer), |
|
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|
6094 returns this integer. |
|
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|
6095 If this argument is absent or is <b>nil</b>, |
|
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|
6096 returns <code>d</code>. |
|
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|
6097 Otherwise, raises an error. |
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changeset
|
6098 |
|
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changeset
|
6099 |
|
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changeset
|
6100 |
|
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changeset
|
6101 |
|
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changeset
|
6102 |
|
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|
6103 <hr><h3><a name="luaL_optlstring"><code>luaL_optlstring</code></a></h3><p> |
|
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|
6104 <span class="apii">[-0, +0, <em>v</em>]</span> |
|
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changeset
|
6105 <pre>const char *luaL_optlstring (lua_State *L, |
|
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6106 int arg, |
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6107 const char *d, |
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6108 size_t *l);</pre> |
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6109 |
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6110 <p> |
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|
6111 If the function argument <code>arg</code> is a string, |
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|
6112 returns this string. |
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6113 If this argument is absent or is <b>nil</b>, |
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6114 returns <code>d</code>. |
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6115 Otherwise, raises an error. |
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6116 |
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6117 |
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6118 <p> |
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6119 If <code>l</code> is not <code>NULL</code>, |
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6120 fills the position <code>*l</code> with the result's length. |
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6121 |
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6122 |
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6123 |
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6124 |
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6125 |
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6126 <hr><h3><a name="luaL_optnumber"><code>luaL_optnumber</code></a></h3><p> |
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6127 <span class="apii">[-0, +0, <em>v</em>]</span> |
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6128 <pre>lua_Number luaL_optnumber (lua_State *L, int arg, lua_Number d);</pre> |
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6129 |
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6130 <p> |
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6131 If the function argument <code>arg</code> is a number, |
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6132 returns this number. |
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6133 If this argument is absent or is <b>nil</b>, |
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6134 returns <code>d</code>. |
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6135 Otherwise, raises an error. |
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6136 |
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6137 |
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|
6138 |
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|
6139 |
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6140 |
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6141 <hr><h3><a name="luaL_optstring"><code>luaL_optstring</code></a></h3><p> |
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6142 <span class="apii">[-0, +0, <em>v</em>]</span> |
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6143 <pre>const char *luaL_optstring (lua_State *L, |
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6144 int arg, |
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6145 const char *d);</pre> |
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6146 |
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6147 <p> |
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6148 If the function argument <code>arg</code> is a string, |
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|
6149 returns this string. |
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6150 If this argument is absent or is <b>nil</b>, |
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|
6151 returns <code>d</code>. |
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6152 Otherwise, raises an error. |
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|
6153 |
|
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|
6154 |
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|
6155 |
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|
6156 |
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6157 |
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6158 <hr><h3><a name="luaL_prepbuffer"><code>luaL_prepbuffer</code></a></h3><p> |
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6159 <span class="apii">[-?, +?, <em>e</em>]</span> |
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6160 <pre>char *luaL_prepbuffer (luaL_Buffer *B);</pre> |
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6161 |
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6162 <p> |
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|
6163 Equivalent to <a href="#luaL_prepbuffsize"><code>luaL_prepbuffsize</code></a> |
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6164 with the predefined size <a name="pdf-LUAL_BUFFERSIZE"><code>LUAL_BUFFERSIZE</code></a>. |
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|
6165 |
|
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|
6166 |
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|
6167 |
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|
6168 |
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|
6169 |
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6170 <hr><h3><a name="luaL_prepbuffsize"><code>luaL_prepbuffsize</code></a></h3><p> |
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6171 <span class="apii">[-?, +?, <em>e</em>]</span> |
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6172 <pre>char *luaL_prepbuffsize (luaL_Buffer *B, size_t sz);</pre> |
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6173 |
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6174 <p> |
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6175 Returns an address to a space of size <code>sz</code> |
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6176 where you can copy a string to be added to buffer <code>B</code> |
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|
6177 (see <a href="#luaL_Buffer"><code>luaL_Buffer</code></a>). |
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|
6178 After copying the string into this space you must call |
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6179 <a href="#luaL_addsize"><code>luaL_addsize</code></a> with the size of the string to actually add |
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|
6180 it to the buffer. |
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|
6181 |
|
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|
6182 |
|
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|
6183 |
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|
6184 |
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|
6185 |
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6186 <hr><h3><a name="luaL_pushresult"><code>luaL_pushresult</code></a></h3><p> |
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6187 <span class="apii">[-?, +1, <em>e</em>]</span> |
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6188 <pre>void luaL_pushresult (luaL_Buffer *B);</pre> |
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|
6189 |
|
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|
6190 <p> |
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6191 Finishes the use of buffer <code>B</code> leaving the final string on |
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|
6192 the top of the stack. |
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|
6193 |
|
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|
6194 |
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|
6195 |
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|
6196 |
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|
6197 |
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6198 <hr><h3><a name="luaL_pushresultsize"><code>luaL_pushresultsize</code></a></h3><p> |
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6199 <span class="apii">[-?, +1, <em>e</em>]</span> |
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6200 <pre>void luaL_pushresultsize (luaL_Buffer *B, size_t sz);</pre> |
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6201 |
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6202 <p> |
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|
6203 Equivalent to the sequence <a href="#luaL_addsize"><code>luaL_addsize</code></a>, <a href="#luaL_pushresult"><code>luaL_pushresult</code></a>. |
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6204 |
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|
6205 |
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|
6206 |
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|
6207 |
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6208 |
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6209 <hr><h3><a name="luaL_ref"><code>luaL_ref</code></a></h3><p> |
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6210 <span class="apii">[-1, +0, <em>e</em>]</span> |
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6211 <pre>int luaL_ref (lua_State *L, int t);</pre> |
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6212 |
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6213 <p> |
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6214 Creates and returns a <em>reference</em>, |
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6215 in the table at index <code>t</code>, |
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6216 for the object at the top of the stack (and pops the object). |
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6217 |
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|
6218 |
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6219 <p> |
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6220 A reference is a unique integer key. |
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6221 As long as you do not manually add integer keys into table <code>t</code>, |
|
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6222 <a href="#luaL_ref"><code>luaL_ref</code></a> ensures the uniqueness of the key it returns. |
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6223 You can retrieve an object referred by reference <code>r</code> |
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6224 by calling <code>lua_rawgeti(L, t, r)</code>. |
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6225 Function <a href="#luaL_unref"><code>luaL_unref</code></a> frees a reference and its associated object. |
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6226 |
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6227 |
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6228 <p> |
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|
6229 If the object at the top of the stack is <b>nil</b>, |
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|
6230 <a href="#luaL_ref"><code>luaL_ref</code></a> returns the constant <a name="pdf-LUA_REFNIL"><code>LUA_REFNIL</code></a>. |
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6231 The constant <a name="pdf-LUA_NOREF"><code>LUA_NOREF</code></a> is guaranteed to be different |
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6232 from any reference returned by <a href="#luaL_ref"><code>luaL_ref</code></a>. |
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6233 |
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|
6234 |
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|
6235 |
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|
6236 |
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6237 |
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6238 <hr><h3><a name="luaL_Reg"><code>luaL_Reg</code></a></h3> |
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6239 <pre>typedef struct luaL_Reg { |
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6240 const char *name; |
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6241 lua_CFunction func; |
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6242 } luaL_Reg;</pre> |
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6243 |
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6244 <p> |
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6245 Type for arrays of functions to be registered by |
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6246 <a href="#luaL_setfuncs"><code>luaL_setfuncs</code></a>. |
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6247 <code>name</code> is the function name and <code>func</code> is a pointer to |
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6248 the function. |
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6249 Any array of <a href="#luaL_Reg"><code>luaL_Reg</code></a> must end with a sentinel entry |
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6250 in which both <code>name</code> and <code>func</code> are <code>NULL</code>. |
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6251 |
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6252 |
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|
6253 |
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|
6254 |
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|
6255 |
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6256 <hr><h3><a name="luaL_requiref"><code>luaL_requiref</code></a></h3><p> |
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6257 <span class="apii">[-0, +1, <em>e</em>]</span> |
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6258 <pre>void luaL_requiref (lua_State *L, const char *modname, |
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6259 lua_CFunction openf, int glb);</pre> |
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6260 |
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6261 <p> |
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6262 If <code>modname</code> is not already present in <a href="#pdf-package.loaded"><code>package.loaded</code></a>, |
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6263 calls function <code>openf</code> with string <code>modname</code> as an argument |
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6264 and sets the call result in <code>package.loaded[modname]</code>, |
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|
6265 as if that function has been called through <a href="#pdf-require"><code>require</code></a>. |
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6266 |
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|
6267 |
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6268 <p> |
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6269 If <code>glb</code> is true, |
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6270 also stores the module into global <code>modname</code>. |
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|
6271 |
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|
6272 |
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6273 <p> |
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6274 Leaves a copy of the module on the stack. |
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|
6275 |
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|
6276 |
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|
6277 |
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|
6278 |
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|
6279 |
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6280 <hr><h3><a name="luaL_setfuncs"><code>luaL_setfuncs</code></a></h3><p> |
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6281 <span class="apii">[-nup, +0, <em>e</em>]</span> |
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6282 <pre>void luaL_setfuncs (lua_State *L, const luaL_Reg *l, int nup);</pre> |
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|
6283 |
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|
6284 <p> |
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6285 Registers all functions in the array <code>l</code> |
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6286 (see <a href="#luaL_Reg"><code>luaL_Reg</code></a>) into the table on the top of the stack |
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6287 (below optional upvalues, see next). |
|
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|
6288 |
|
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|
6289 |
|
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|
6290 <p> |
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|
6291 When <code>nup</code> is not zero, |
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|
6292 all functions are created sharing <code>nup</code> upvalues, |
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|
6293 which must be previously pushed on the stack |
|
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|
6294 on top of the library table. |
|
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|
6295 These values are popped from the stack after the registration. |
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|
6296 |
|
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|
6297 |
|
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|
6298 |
|
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|
6299 |
|
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|
6300 |
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|
6301 <hr><h3><a name="luaL_setmetatable"><code>luaL_setmetatable</code></a></h3><p> |
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6302 <span class="apii">[-0, +0, –]</span> |
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6303 <pre>void luaL_setmetatable (lua_State *L, const char *tname);</pre> |
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|
6304 |
|
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6305 <p> |
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6306 Sets the metatable of the object at the top of the stack |
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6307 as the metatable associated with name <code>tname</code> |
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6308 in the registry (see <a href="#luaL_newmetatable"><code>luaL_newmetatable</code></a>). |
|
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|
6309 |
|
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|
6310 |
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|
6311 |
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|
6312 |
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6313 |
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6314 <hr><h3><a name="luaL_Stream"><code>luaL_Stream</code></a></h3> |
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6315 <pre>typedef struct luaL_Stream { |
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|
6316 FILE *f; |
|
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6317 lua_CFunction closef; |
|
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6318 } luaL_Stream;</pre> |
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6319 |
|
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6320 <p> |
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6321 The standard representation for file handles, |
|
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6322 which is used by the standard I/O library. |
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6323 |
|
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|
6324 |
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6325 <p> |
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6326 A file handle is implemented as a full userdata, |
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6327 with a metatable called <code>LUA_FILEHANDLE</code> |
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6328 (where <code>LUA_FILEHANDLE</code> is a macro with the actual metatable's name). |
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6329 The metatable is created by the I/O library |
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6330 (see <a href="#luaL_newmetatable"><code>luaL_newmetatable</code></a>). |
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6331 |
|
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|
6332 |
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6333 <p> |
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6334 This userdata must start with the structure <code>luaL_Stream</code>; |
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6335 it can contain other data after this initial structure. |
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|
6336 Field <code>f</code> points to the corresponding C stream |
|
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|
6337 (or it can be <code>NULL</code> to indicate an incompletely created handle). |
|
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|
6338 Field <code>closef</code> points to a Lua function |
|
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|
6339 that will be called to close the stream |
|
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|
6340 when the handle is closed or collected; |
|
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|
6341 this function receives the file handle as its sole argument and |
|
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|
6342 must return either <b>true</b> (in case of success) |
|
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|
6343 or <b>nil</b> plus an error message (in case of error). |
|
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|
6344 Once Lua calls this field, |
|
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|
6345 the field value is changed to <code>NULL</code> |
|
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|
6346 to signal that the handle is closed. |
|
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|
6347 |
|
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|
6348 |
|
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Franklin Schmidt <fschmidt@gmail.com>
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diff
changeset
|
6349 |
|
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Franklin Schmidt <fschmidt@gmail.com>
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|
6350 |
|
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Franklin Schmidt <fschmidt@gmail.com>
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diff
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|
6351 |
|
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|
6352 <hr><h3><a name="luaL_testudata"><code>luaL_testudata</code></a></h3><p> |
|
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|
6353 <span class="apii">[-0, +0, <em>e</em>]</span> |
|
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|
6354 <pre>void *luaL_testudata (lua_State *L, int arg, const char *tname);</pre> |
|
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|
6355 |
|
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|
6356 <p> |
|
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|
6357 This function works like <a href="#luaL_checkudata"><code>luaL_checkudata</code></a>, |
|
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|
6358 except that, when the test fails, |
|
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|
6359 it returns <code>NULL</code> instead of raising an error. |
|
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|
6360 |
|
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Franklin Schmidt <fschmidt@gmail.com>
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diff
changeset
|
6361 |
|
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Franklin Schmidt <fschmidt@gmail.com>
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diff
changeset
|
6362 |
|
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Franklin Schmidt <fschmidt@gmail.com>
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diff
changeset
|
6363 |
|
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Franklin Schmidt <fschmidt@gmail.com>
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diff
changeset
|
6364 |
|
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|
6365 <hr><h3><a name="luaL_tolstring"><code>luaL_tolstring</code></a></h3><p> |
|
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|
6366 <span class="apii">[-0, +1, <em>e</em>]</span> |
|
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|
6367 <pre>const char *luaL_tolstring (lua_State *L, int idx, size_t *len);</pre> |
|
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|
6368 |
|
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|
6369 <p> |
|
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|
6370 Converts any Lua value at the given index to a C string |
|
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|
6371 in a reasonable format. |
|
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diff
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|
6372 The resulting string is pushed onto the stack and also |
|
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|
6373 returned by the function. |
|
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|
6374 If <code>len</code> is not <code>NULL</code>, |
|
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|
6375 the function also sets <code>*len</code> with the string length. |
|
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|
6376 |
|
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|
6377 |
|
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|
6378 <p> |
|
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|
6379 If the value has a metatable with a <code>"__tostring"</code> field, |
|
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|
6380 then <code>luaL_tolstring</code> calls the corresponding metamethod |
|
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|
6381 with the value as argument, |
|
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|
6382 and uses the result of the call as its result. |
|
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|
6383 |
|
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diff
changeset
|
6384 |
|
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Franklin Schmidt <fschmidt@gmail.com>
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diff
changeset
|
6385 |
|
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changeset
|
6386 |
|
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changeset
|
6387 |
|
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|
6388 <hr><h3><a name="luaL_traceback"><code>luaL_traceback</code></a></h3><p> |
|
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|
6389 <span class="apii">[-0, +1, <em>e</em>]</span> |
|
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|
6390 <pre>void luaL_traceback (lua_State *L, lua_State *L1, const char *msg, |
|
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|
6391 int level);</pre> |
|
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|
6392 |
|
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|
6393 <p> |
|
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|
6394 Creates and pushes a traceback of the stack <code>L1</code>. |
|
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|
6395 If <code>msg</code> is not <code>NULL</code> it is appended |
|
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|
6396 at the beginning of the traceback. |
|
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|
6397 The <code>level</code> parameter tells at which level |
|
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|
6398 to start the traceback. |
|
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changeset
|
6399 |
|
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Franklin Schmidt <fschmidt@gmail.com>
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diff
changeset
|
6400 |
|
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Franklin Schmidt <fschmidt@gmail.com>
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diff
changeset
|
6401 |
|
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Franklin Schmidt <fschmidt@gmail.com>
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diff
changeset
|
6402 |
|
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Franklin Schmidt <fschmidt@gmail.com>
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diff
changeset
|
6403 |
|
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|
6404 <hr><h3><a name="luaL_typename"><code>luaL_typename</code></a></h3><p> |
|
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|
6405 <span class="apii">[-0, +0, –]</span> |
|
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|
6406 <pre>const char *luaL_typename (lua_State *L, int index);</pre> |
|
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|
6407 |
|
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|
6408 <p> |
|
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|
6409 Returns the name of the type of the value at the given index. |
|
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changeset
|
6410 |
|
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diff
changeset
|
6411 |
|
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Franklin Schmidt <fschmidt@gmail.com>
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diff
changeset
|
6412 |
|
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diff
changeset
|
6413 |
|
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Franklin Schmidt <fschmidt@gmail.com>
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diff
changeset
|
6414 |
|
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|
6415 <hr><h3><a name="luaL_unref"><code>luaL_unref</code></a></h3><p> |
|
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|
6416 <span class="apii">[-0, +0, –]</span> |
|
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|
6417 <pre>void luaL_unref (lua_State *L, int t, int ref);</pre> |
|
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|
6418 |
|
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|
6419 <p> |
|
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changeset
|
6420 Releases reference <code>ref</code> from the table at index <code>t</code> |
|
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|
6421 (see <a href="#luaL_ref"><code>luaL_ref</code></a>). |
|
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|
6422 The entry is removed from the table, |
|
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changeset
|
6423 so that the referred object can be collected. |
|
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|
6424 The reference <code>ref</code> is also freed to be used again. |
|
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changeset
|
6425 |
|
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changeset
|
6426 |
|
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|
6427 <p> |
|
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|
6428 If <code>ref</code> is <a href="#pdf-LUA_NOREF"><code>LUA_NOREF</code></a> or <a href="#pdf-LUA_REFNIL"><code>LUA_REFNIL</code></a>, |
|
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|
6429 <a href="#luaL_unref"><code>luaL_unref</code></a> does nothing. |
|
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changeset
|
6430 |
|
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diff
changeset
|
6431 |
|
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diff
changeset
|
6432 |
|
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diff
changeset
|
6433 |
|
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diff
changeset
|
6434 |
|
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|
6435 <hr><h3><a name="luaL_where"><code>luaL_where</code></a></h3><p> |
|
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6436 <span class="apii">[-0, +1, <em>e</em>]</span> |
|
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|
6437 <pre>void luaL_where (lua_State *L, int lvl);</pre> |
|
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|
6438 |
|
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|
6439 <p> |
|
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|
6440 Pushes onto the stack a string identifying the current position |
|
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|
6441 of the control at level <code>lvl</code> in the call stack. |
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|
6442 Typically this string has the following format: |
|
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changeset
|
6443 |
|
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|
6444 <pre> |
|
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|
6445 <em>chunkname</em>:<em>currentline</em>: |
|
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|
6446 </pre><p> |
|
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|
6447 Level 0 is the running function, |
|
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|
6448 level 1 is the function that called the running function, |
|
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|
6449 etc. |
|
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changeset
|
6450 |
|
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6451 |
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|
6452 <p> |
|
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|
6453 This function is used to build a prefix for error messages. |
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6454 |
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|
6455 |
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6456 |
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6457 |
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6458 |
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6459 |
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6460 |
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|
6461 <h1>6 – <a name="6">Standard Libraries</a></h1> |
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6462 |
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6463 <p> |
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|
6464 The standard Lua libraries provide useful functions |
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|
6465 that are implemented directly through the C API. |
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|
6466 Some of these functions provide essential services to the language |
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6467 (e.g., <a href="#pdf-type"><code>type</code></a> and <a href="#pdf-getmetatable"><code>getmetatable</code></a>); |
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6468 others provide access to "outside" services (e.g., I/O); |
|
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6469 and others could be implemented in Lua itself, |
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6470 but are quite useful or have critical performance requirements that |
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6471 deserve an implementation in C (e.g., <a href="#pdf-table.sort"><code>table.sort</code></a>). |
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6472 |
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6473 |
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6474 <p> |
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6475 All libraries are implemented through the official C API |
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6476 and are provided as separate C modules. |
|
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|
6477 Currently, Lua has the following standard libraries: |
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6478 |
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|
6479 <ul> |
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6480 |
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|
6481 <li>basic library (<a href="#6.1">§6.1</a>);</li> |
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6482 |
|
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|
6483 <li>coroutine library (<a href="#6.2">§6.2</a>);</li> |
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6484 |
|
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|
6485 <li>package library (<a href="#6.3">§6.3</a>);</li> |
|
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|
6486 |
|
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|
6487 <li>string manipulation (<a href="#6.4">§6.4</a>);</li> |
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|
6488 |
|
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|
6489 <li>basic UTF-8 support (<a href="#6.5">§6.5</a>);</li> |
|
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|
6490 |
|
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|
6491 <li>table manipulation (<a href="#6.6">§6.6</a>);</li> |
|
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|
6492 |
|
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|
6493 <li>mathematical functions (<a href="#6.7">§6.7</a>) (sin, log, etc.);</li> |
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|
6494 |
|
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|
6495 <li>input and output (<a href="#6.8">§6.8</a>);</li> |
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|
6496 |
|
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|
6497 <li>operating system facilities (<a href="#6.9">§6.9</a>);</li> |
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|
6498 |
|
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|
6499 <li>debug facilities (<a href="#6.10">§6.10</a>).</li> |
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6500 |
|
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|
6501 </ul><p> |
|
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|
6502 Except for the basic and the package libraries, |
|
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|
6503 each library provides all its functions as fields of a global table |
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|
6504 or as methods of its objects. |
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6505 |
|
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|
6506 |
|
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|
6507 <p> |
|
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|
6508 To have access to these libraries, |
|
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|
6509 the C host program should call the <a href="#luaL_openlibs"><code>luaL_openlibs</code></a> function, |
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|
6510 which opens all standard libraries. |
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|
6511 Alternatively, |
|
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|
6512 the host program can open them individually by using |
|
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|
6513 <a href="#luaL_requiref"><code>luaL_requiref</code></a> to call |
|
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|
6514 <a name="pdf-luaopen_base"><code>luaopen_base</code></a> (for the basic library), |
|
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|
6515 <a name="pdf-luaopen_package"><code>luaopen_package</code></a> (for the package library), |
|
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6516 <a name="pdf-luaopen_coroutine"><code>luaopen_coroutine</code></a> (for the coroutine library), |
|
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|
6517 <a name="pdf-luaopen_string"><code>luaopen_string</code></a> (for the string library), |
|
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|
6518 <a name="pdf-luaopen_utf8"><code>luaopen_utf8</code></a> (for the UTF8 library), |
|
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|
6519 <a name="pdf-luaopen_table"><code>luaopen_table</code></a> (for the table library), |
|
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|
6520 <a name="pdf-luaopen_math"><code>luaopen_math</code></a> (for the mathematical library), |
|
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|
6521 <a name="pdf-luaopen_io"><code>luaopen_io</code></a> (for the I/O library), |
|
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|
6522 <a name="pdf-luaopen_os"><code>luaopen_os</code></a> (for the operating system library), |
|
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|
6523 and <a name="pdf-luaopen_debug"><code>luaopen_debug</code></a> (for the debug library). |
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|
6524 These functions are declared in <a name="pdf-lualib.h"><code>lualib.h</code></a>. |
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6525 |
|
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|
6526 |
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|
6527 |
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|
6528 <h2>6.1 – <a name="6.1">Basic Functions</a></h2> |
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6529 |
|
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|
6530 <p> |
|
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|
6531 The basic library provides core functions to Lua. |
|
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|
6532 If you do not include this library in your application, |
|
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|
6533 you should check carefully whether you need to provide |
|
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|
6534 implementations for some of its facilities. |
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6535 |
|
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|
6536 |
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6537 <p> |
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|
6538 <hr><h3><a name="pdf-assert"><code>assert (v [, message])</code></a></h3> |
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6539 |
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6540 |
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6541 <p> |
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6542 Calls <a href="#pdf-error"><code>error</code></a> if |
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6543 the value of its argument <code>v</code> is false (i.e., <b>nil</b> or <b>false</b>); |
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6544 otherwise, returns all its arguments. |
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6545 In case of error, |
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6546 <code>message</code> is the error object; |
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6547 when absent, it defaults to "<code>assertion failed!</code>" |
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6548 |
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|
6549 |
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6550 |
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6551 |
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6552 <p> |
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6553 <hr><h3><a name="pdf-collectgarbage"><code>collectgarbage ([opt [, arg]])</code></a></h3> |
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6554 |
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6555 |
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6556 <p> |
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6557 This function is a generic interface to the garbage collector. |
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6558 It performs different functions according to its first argument, <code>opt</code>: |
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6559 |
|
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|
6560 <ul> |
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6561 |
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6562 <li><b>"<code>collect</code>": </b> |
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6563 performs a full garbage-collection cycle. |
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6564 This is the default option. |
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|
6565 </li> |
|
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|
6566 |
|
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6567 <li><b>"<code>stop</code>": </b> |
|
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|
6568 stops automatic execution of the garbage collector. |
|
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|
6569 The collector will run only when explicitly invoked, |
|
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|
6570 until a call to restart it. |
|
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|
6571 </li> |
|
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|
6572 |
|
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|
6573 <li><b>"<code>restart</code>": </b> |
|
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|
6574 restarts automatic execution of the garbage collector. |
|
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|
6575 </li> |
|
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|
6576 |
|
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6577 <li><b>"<code>count</code>": </b> |
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6578 returns the total memory in use by Lua in Kbytes. |
|
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6579 The value has a fractional part, |
|
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|
6580 so that it multiplied by 1024 |
|
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6581 gives the exact number of bytes in use by Lua |
|
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6582 (except for overflows). |
|
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6583 </li> |
|
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|
6584 |
|
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6585 <li><b>"<code>step</code>": </b> |
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6586 performs a garbage-collection step. |
|
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6587 The step "size" is controlled by <code>arg</code>. |
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6588 With a zero value, |
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6589 the collector will perform one basic (indivisible) step. |
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6590 For non-zero values, |
|
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6591 the collector will perform as if that amount of memory |
|
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6592 (in KBytes) had been allocated by Lua. |
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6593 Returns <b>true</b> if the step finished a collection cycle. |
|
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|
6594 </li> |
|
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|
6595 |
|
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|
6596 <li><b>"<code>setpause</code>": </b> |
|
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|
6597 sets <code>arg</code> as the new value for the <em>pause</em> of |
|
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6598 the collector (see <a href="#2.5">§2.5</a>). |
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6599 Returns the previous value for <em>pause</em>. |
|
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6600 </li> |
|
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|
6601 |
|
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|
6602 <li><b>"<code>setstepmul</code>": </b> |
|
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|
6603 sets <code>arg</code> as the new value for the <em>step multiplier</em> of |
|
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|
6604 the collector (see <a href="#2.5">§2.5</a>). |
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6605 Returns the previous value for <em>step</em>. |
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6606 </li> |
|
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|
6607 |
|
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6608 <li><b>"<code>isrunning</code>": </b> |
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6609 returns a boolean that tells whether the collector is running |
|
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6610 (i.e., not stopped). |
|
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6611 </li> |
|
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|
6612 |
|
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|
6613 </ul> |
|
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|
6614 |
|
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|
6615 |
|
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6616 |
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6617 <p> |
|
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6618 <hr><h3><a name="pdf-dofile"><code>dofile ([filename])</code></a></h3> |
|
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6619 Opens the named file and executes its contents as a Lua chunk. |
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6620 When called without arguments, |
|
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|
6621 <code>dofile</code> executes the contents of the standard input (<code>stdin</code>). |
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6622 Returns all values returned by the chunk. |
|
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6623 In case of errors, <code>dofile</code> propagates the error |
|
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6624 to its caller (that is, <code>dofile</code> does not run in protected mode). |
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|
6625 |
|
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|
6626 |
|
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|
6627 |
|
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|
6628 |
|
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|
6629 <p> |
|
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|
6630 <hr><h3><a name="pdf-error"><code>error (message [, level])</code></a></h3> |
|
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|
6631 Terminates the last protected function called |
|
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6632 and returns <code>message</code> as the error object. |
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|
6633 Function <code>error</code> never returns. |
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|
6634 |
|
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|
6635 |
|
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|
6636 <p> |
|
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|
6637 Usually, <code>error</code> adds some information about the error position |
|
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6638 at the beginning of the message, if the message is a string. |
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|
6639 The <code>level</code> argument specifies how to get the error position. |
|
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|
6640 With level 1 (the default), the error position is where the |
|
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|
6641 <code>error</code> function was called. |
|
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|
6642 Level 2 points the error to where the function |
|
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|
6643 that called <code>error</code> was called; and so on. |
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6644 Passing a level 0 avoids the addition of error position information |
|
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|
6645 to the message. |
|
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|
6646 |
|
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|
6647 |
|
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|
6648 |
|
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|
6649 |
|
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|
6650 <p> |
|
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|
6651 <hr><h3><a name="pdf-_G"><code>_G</code></a></h3> |
|
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6652 A global variable (not a function) that |
|
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|
6653 holds the global environment (see <a href="#2.2">§2.2</a>). |
|
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6654 Lua itself does not use this variable; |
|
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|
6655 changing its value does not affect any environment, |
|
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|
6656 nor vice versa. |
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|
6657 |
|
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|
6658 |
|
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|
6659 |
|
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|
6660 |
|
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|
6661 <p> |
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|
6662 <hr><h3><a name="pdf-getmetatable"><code>getmetatable (object)</code></a></h3> |
|
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|
6663 |
|
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|
6664 |
|
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|
6665 <p> |
|
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|
6666 If <code>object</code> does not have a metatable, returns <b>nil</b>. |
|
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6667 Otherwise, |
|
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|
6668 if the object's metatable has a <code>"__metatable"</code> field, |
|
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|
6669 returns the associated value. |
|
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|
6670 Otherwise, returns the metatable of the given object. |
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|
6671 |
|
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|
6672 |
|
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|
6673 |
|
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|
6674 |
|
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|
6675 <p> |
|
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|
6676 <hr><h3><a name="pdf-ipairs"><code>ipairs (t)</code></a></h3> |
|
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|
6677 |
|
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|
6678 |
|
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|
6679 <p> |
|
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|
6680 Returns three values (an iterator function, the table <code>t</code>, and 0) |
|
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|
6681 so that the construction |
|
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|
6682 |
|
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|
6683 <pre> |
|
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6684 for i,v in ipairs(t) do <em>body</em> end |
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6685 </pre><p> |
|
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6686 will iterate over the key–value pairs |
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6687 (<code>1,t[1]</code>), (<code>2,t[2]</code>), ..., |
|
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|
6688 up to the first nil value. |
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|
6689 |
|
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|
6690 |
|
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|
6691 |
|
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6692 |
|
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6693 <p> |
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6694 <hr><h3><a name="pdf-load"><code>load (chunk [, chunkname [, mode [, env]]])</code></a></h3> |
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6695 |
|
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6696 |
|
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6697 <p> |
|
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6698 Loads a chunk. |
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6699 |
|
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6700 |
|
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6701 <p> |
|
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|
6702 If <code>chunk</code> is a string, the chunk is this string. |
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6703 If <code>chunk</code> is a function, |
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6704 <code>load</code> calls it repeatedly to get the chunk pieces. |
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|
6705 Each call to <code>chunk</code> must return a string that concatenates |
|
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6706 with previous results. |
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6707 A return of an empty string, <b>nil</b>, or no value signals the end of the chunk. |
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6708 |
|
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|
6709 |
|
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6710 <p> |
|
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6711 If there are no syntactic errors, |
|
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6712 returns the compiled chunk as a function; |
|
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6713 otherwise, returns <b>nil</b> plus the error message. |
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6714 |
|
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|
6715 |
|
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6716 <p> |
|
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|
6717 If the resulting function has upvalues, |
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|
6718 the first upvalue is set to the value of <code>env</code>, |
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6719 if that parameter is given, |
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6720 or to the value of the global environment. |
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6721 Other upvalues are initialized with <b>nil</b>. |
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6722 (When you load a main chunk, |
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6723 the resulting function will always have exactly one upvalue, |
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6724 the <code>_ENV</code> variable (see <a href="#2.2">§2.2</a>). |
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6725 However, |
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6726 when you load a binary chunk created from a function (see <a href="#pdf-string.dump"><code>string.dump</code></a>), |
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6727 the resulting function can have an arbitrary number of upvalues.) |
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6728 All upvalues are fresh, that is, |
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6729 they are not shared with any other function. |
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6730 |
|
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|
6731 |
|
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6732 <p> |
|
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6733 <code>chunkname</code> is used as the name of the chunk for error messages |
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|
6734 and debug information (see <a href="#4.9">§4.9</a>). |
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6735 When absent, |
|
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6736 it defaults to <code>chunk</code>, if <code>chunk</code> is a string, |
|
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6737 or to "<code>=(load)</code>" otherwise. |
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|
6738 |
|
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|
6739 |
|
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|
6740 <p> |
|
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|
6741 The string <code>mode</code> controls whether the chunk can be text or binary |
|
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6742 (that is, a precompiled chunk). |
|
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|
6743 It may be the string "<code>b</code>" (only binary chunks), |
|
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6744 "<code>t</code>" (only text chunks), |
|
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6745 or "<code>bt</code>" (both binary and text). |
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|
6746 The default is "<code>bt</code>". |
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6747 |
|
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|
6748 |
|
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|
6749 <p> |
|
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|
6750 Lua does not check the consistency of binary chunks. |
|
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|
6751 Maliciously crafted binary chunks can crash |
|
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|
6752 the interpreter. |
|
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|
6753 |
|
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|
6754 |
|
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|
6755 |
|
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|
6756 |
|
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|
6757 <p> |
|
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|
6758 <hr><h3><a name="pdf-loadfile"><code>loadfile ([filename [, mode [, env]]])</code></a></h3> |
|
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|
6759 |
|
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|
6760 |
|
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|
6761 <p> |
|
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|
6762 Similar to <a href="#pdf-load"><code>load</code></a>, |
|
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6763 but gets the chunk from file <code>filename</code> |
|
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|
6764 or from the standard input, |
|
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|
6765 if no file name is given. |
|
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|
6766 |
|
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|
6767 |
|
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|
6768 |
|
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|
6769 |
|
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|
6770 <p> |
|
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|
6771 <hr><h3><a name="pdf-next"><code>next (table [, index])</code></a></h3> |
|
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|
6772 |
|
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|
6773 |
|
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|
6774 <p> |
|
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|
6775 Allows a program to traverse all fields of a table. |
|
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|
6776 Its first argument is a table and its second argument |
|
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6777 is an index in this table. |
|
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6778 <code>next</code> returns the next index of the table |
|
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|
6779 and its associated value. |
|
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|
6780 When called with <b>nil</b> as its second argument, |
|
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|
6781 <code>next</code> returns an initial index |
|
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|
6782 and its associated value. |
|
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6783 When called with the last index, |
|
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6784 or with <b>nil</b> in an empty table, |
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6785 <code>next</code> returns <b>nil</b>. |
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|
6786 If the second argument is absent, then it is interpreted as <b>nil</b>. |
|
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|
6787 In particular, |
|
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|
6788 you can use <code>next(t)</code> to check whether a table is empty. |
|
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|
6789 |
|
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|
6790 |
|
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|
6791 <p> |
|
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6792 The order in which the indices are enumerated is not specified, |
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6793 <em>even for numeric indices</em>. |
|
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6794 (To traverse a table in numeric order, |
|
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6795 use a numerical <b>for</b>.) |
|
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6796 |
|
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|
6797 |
|
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|
6798 <p> |
|
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|
6799 The behavior of <code>next</code> is undefined if, |
|
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6800 during the traversal, |
|
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|
6801 you assign any value to a non-existent field in the table. |
|
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|
6802 You may however modify existing fields. |
|
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|
6803 In particular, you may clear existing fields. |
|
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|
6804 |
|
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diff
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|
6805 |
|
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diff
changeset
|
6806 |
|
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diff
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|
6807 |
|
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|
6808 <p> |
|
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|
6809 <hr><h3><a name="pdf-pairs"><code>pairs (t)</code></a></h3> |
|
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|
6810 |
|
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|
6811 |
|
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|
6812 <p> |
|
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|
6813 If <code>t</code> has a metamethod <code>__pairs</code>, |
|
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|
6814 calls it with <code>t</code> as argument and returns the first three |
|
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|
6815 results from the call. |
|
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|
6816 |
|
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|
6817 |
|
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|
6818 <p> |
|
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|
6819 Otherwise, |
|
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|
6820 returns three values: the <a href="#pdf-next"><code>next</code></a> function, the table <code>t</code>, and <b>nil</b>, |
|
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|
6821 so that the construction |
|
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|
6822 |
|
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|
6823 <pre> |
|
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|
6824 for k,v in pairs(t) do <em>body</em> end |
|
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|
6825 </pre><p> |
|
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|
6826 will iterate over all key–value pairs of table <code>t</code>. |
|
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|
6827 |
|
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|
6828 |
|
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|
6829 <p> |
|
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|
6830 See function <a href="#pdf-next"><code>next</code></a> for the caveats of modifying |
|
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|
6831 the table during its traversal. |
|
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|
6832 |
|
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diff
changeset
|
6833 |
|
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diff
changeset
|
6834 |
|
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diff
changeset
|
6835 |
|
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|
6836 <p> |
|
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|
6837 <hr><h3><a name="pdf-pcall"><code>pcall (f [, arg1, ···])</code></a></h3> |
|
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|
6838 |
|
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diff
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|
6839 |
|
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|
6840 <p> |
|
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|
6841 Calls function <code>f</code> with |
|
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|
6842 the given arguments in <em>protected mode</em>. |
|
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|
6843 This means that any error inside <code>f</code> is not propagated; |
|
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|
6844 instead, <code>pcall</code> catches the error |
|
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|
6845 and returns a status code. |
|
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diff
changeset
|
6846 Its first result is the status code (a boolean), |
|
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parents:
diff
changeset
|
6847 which is true if the call succeeds without errors. |
|
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|
6848 In such case, <code>pcall</code> also returns all results from the call, |
|
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|
6849 after this first result. |
|
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|
6850 In case of any error, <code>pcall</code> returns <b>false</b> plus the error message. |
|
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changeset
|
6851 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
6852 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
6853 |
|
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Franklin Schmidt <fschmidt@gmail.com>
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diff
changeset
|
6854 |
|
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|
6855 <p> |
|
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|
6856 <hr><h3><a name="pdf-print"><code>print (···)</code></a></h3> |
|
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|
6857 Receives any number of arguments |
|
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|
6858 and prints their values to <code>stdout</code>, |
|
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|
6859 using the <a href="#pdf-tostring"><code>tostring</code></a> function to convert each argument to a string. |
|
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changeset
|
6860 <code>print</code> is not intended for formatted output, |
|
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changeset
|
6861 but only as a quick way to show a value, |
|
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diff
changeset
|
6862 for instance for debugging. |
|
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diff
changeset
|
6863 For complete control over the output, |
|
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diff
changeset
|
6864 use <a href="#pdf-string.format"><code>string.format</code></a> and <a href="#pdf-io.write"><code>io.write</code></a>. |
|
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changeset
|
6865 |
|
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parents:
diff
changeset
|
6866 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
6867 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
6868 |
|
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Franklin Schmidt <fschmidt@gmail.com>
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changeset
|
6869 <p> |
|
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changeset
|
6870 <hr><h3><a name="pdf-rawequal"><code>rawequal (v1, v2)</code></a></h3> |
|
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|
6871 Checks whether <code>v1</code> is equal to <code>v2</code>, |
|
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changeset
|
6872 without invoking any metamethod. |
|
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parents:
diff
changeset
|
6873 Returns a boolean. |
|
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diff
changeset
|
6874 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
6875 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
6876 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
6877 |
|
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diff
changeset
|
6878 <p> |
|
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changeset
|
6879 <hr><h3><a name="pdf-rawget"><code>rawget (table, index)</code></a></h3> |
|
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|
6880 Gets the real value of <code>table[index]</code>, |
|
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changeset
|
6881 without invoking any metamethod. |
|
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diff
changeset
|
6882 <code>table</code> must be a table; |
|
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changeset
|
6883 <code>index</code> may be any value. |
|
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changeset
|
6884 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
6885 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
6886 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
6887 |
|
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changeset
|
6888 <p> |
|
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changeset
|
6889 <hr><h3><a name="pdf-rawlen"><code>rawlen (v)</code></a></h3> |
|
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changeset
|
6890 Returns the length of the object <code>v</code>, |
|
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changeset
|
6891 which must be a table or a string, |
|
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changeset
|
6892 without invoking any metamethod. |
|
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changeset
|
6893 Returns an integer. |
|
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changeset
|
6894 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
6895 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
6896 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
6897 |
|
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parents:
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changeset
|
6898 <p> |
|
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changeset
|
6899 <hr><h3><a name="pdf-rawset"><code>rawset (table, index, value)</code></a></h3> |
|
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changeset
|
6900 Sets the real value of <code>table[index]</code> to <code>value</code>, |
|
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changeset
|
6901 without invoking any metamethod. |
|
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diff
changeset
|
6902 <code>table</code> must be a table, |
|
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changeset
|
6903 <code>index</code> any value different from <b>nil</b> and NaN, |
|
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changeset
|
6904 and <code>value</code> any Lua value. |
|
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changeset
|
6905 |
|
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parents:
diff
changeset
|
6906 |
|
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changeset
|
6907 <p> |
|
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changeset
|
6908 This function returns <code>table</code>. |
|
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changeset
|
6909 |
|
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parents:
diff
changeset
|
6910 |
|
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parents:
diff
changeset
|
6911 |
|
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diff
changeset
|
6912 |
|
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changeset
|
6913 <p> |
|
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changeset
|
6914 <hr><h3><a name="pdf-select"><code>select (index, ···)</code></a></h3> |
|
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changeset
|
6915 |
|
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diff
changeset
|
6916 |
|
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changeset
|
6917 <p> |
|
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diff
changeset
|
6918 If <code>index</code> is a number, |
|
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changeset
|
6919 returns all arguments after argument number <code>index</code>; |
|
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|
6920 a negative number indexes from the end (-1 is the last argument). |
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|
6921 Otherwise, <code>index</code> must be the string <code>"#"</code>, |
|
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|
6922 and <code>select</code> returns the total number of extra arguments it received. |
|
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|
6923 |
|
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diff
changeset
|
6924 |
|
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diff
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|
6925 |
|
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|
6926 |
|
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|
6927 <p> |
|
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|
6928 <hr><h3><a name="pdf-setmetatable"><code>setmetatable (table, metatable)</code></a></h3> |
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|
6929 |
|
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|
6930 |
|
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|
6931 <p> |
|
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|
6932 Sets the metatable for the given table. |
|
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|
6933 (You cannot change the metatable of other types from Lua, only from C.) |
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|
6934 If <code>metatable</code> is <b>nil</b>, |
|
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|
6935 removes the metatable of the given table. |
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|
6936 If the original metatable has a <code>"__metatable"</code> field, |
|
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|
6937 raises an error. |
|
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|
6938 |
|
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|
6939 |
|
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|
6940 <p> |
|
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|
6941 This function returns <code>table</code>. |
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|
6942 |
|
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diff
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|
6943 |
|
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diff
changeset
|
6944 |
|
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diff
changeset
|
6945 |
|
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|
6946 <p> |
|
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|
6947 <hr><h3><a name="pdf-tonumber"><code>tonumber (e [, base])</code></a></h3> |
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|
6948 |
|
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|
6949 |
|
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|
6950 <p> |
|
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|
6951 When called with no <code>base</code>, |
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|
6952 <code>tonumber</code> tries to convert its argument to a number. |
|
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|
6953 If the argument is already a number or |
|
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|
6954 a string convertible to a number, |
|
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|
6955 then <code>tonumber</code> returns this number; |
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|
6956 otherwise, it returns <b>nil</b>. |
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|
6957 |
|
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changeset
|
6958 |
|
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|
6959 <p> |
|
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|
6960 The conversion of strings can result in integers or floats, |
|
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|
6961 according to the lexical conventions of Lua (see <a href="#3.1">§3.1</a>). |
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|
6962 (The string may have leading and trailing spaces and a sign.) |
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|
6963 |
|
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|
6964 |
|
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|
6965 <p> |
|
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|
6966 When called with <code>base</code>, |
|
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|
6967 then <code>e</code> must be a string to be interpreted as |
|
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|
6968 an integer numeral in that base. |
|
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|
6969 The base may be any integer between 2 and 36, inclusive. |
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|
6970 In bases above 10, the letter '<code>A</code>' (in either upper or lower case) |
|
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|
6971 represents 10, '<code>B</code>' represents 11, and so forth, |
|
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|
6972 with '<code>Z</code>' representing 35. |
|
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|
6973 If the string <code>e</code> is not a valid numeral in the given base, |
|
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|
6974 the function returns <b>nil</b>. |
|
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changeset
|
6975 |
|
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diff
changeset
|
6976 |
|
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parents:
diff
changeset
|
6977 |
|
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diff
changeset
|
6978 |
|
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|
6979 <p> |
|
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|
6980 <hr><h3><a name="pdf-tostring"><code>tostring (v)</code></a></h3> |
|
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|
6981 Receives a value of any type and |
|
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|
6982 converts it to a string in a human-readable format. |
|
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|
6983 Floats always produce strings with some |
|
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|
6984 floating-point indication (either a decimal dot or an exponent). |
|
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changeset
|
6985 (For complete control of how numbers are converted, |
|
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|
6986 use <a href="#pdf-string.format"><code>string.format</code></a>.) |
|
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changeset
|
6987 |
|
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diff
changeset
|
6988 |
|
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|
6989 <p> |
|
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changeset
|
6990 If the metatable of <code>v</code> has a <code>"__tostring"</code> field, |
|
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|
6991 then <code>tostring</code> calls the corresponding value |
|
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|
6992 with <code>v</code> as argument, |
|
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diff
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|
6993 and uses the result of the call as its result. |
|
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changeset
|
6994 |
|
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diff
changeset
|
6995 |
|
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Franklin Schmidt <fschmidt@gmail.com>
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diff
changeset
|
6996 |
|
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diff
changeset
|
6997 |
|
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changeset
|
6998 <p> |
|
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|
6999 <hr><h3><a name="pdf-type"><code>type (v)</code></a></h3> |
|
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|
7000 Returns the type of its only argument, coded as a string. |
|
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|
7001 The possible results of this function are |
|
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changeset
|
7002 "<code>nil</code>" (a string, not the value <b>nil</b>), |
|
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changeset
|
7003 "<code>number</code>", |
|
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changeset
|
7004 "<code>string</code>", |
|
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changeset
|
7005 "<code>boolean</code>", |
|
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changeset
|
7006 "<code>table</code>", |
|
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changeset
|
7007 "<code>function</code>", |
|
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changeset
|
7008 "<code>thread</code>", |
|
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changeset
|
7009 and "<code>userdata</code>". |
|
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changeset
|
7010 |
|
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diff
changeset
|
7011 |
|
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diff
changeset
|
7012 |
|
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changeset
|
7013 |
|
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changeset
|
7014 <p> |
|
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|
7015 <hr><h3><a name="pdf-_VERSION"><code>_VERSION</code></a></h3> |
|
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|
7016 A global variable (not a function) that |
|
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changeset
|
7017 holds a string containing the current interpreter version. |
|
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|
7018 The current value of this variable is "<code>Lua 5.3</code>". |
|
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changeset
|
7019 |
|
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diff
changeset
|
7020 |
|
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diff
changeset
|
7021 |
|
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diff
changeset
|
7022 |
|
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changeset
|
7023 <p> |
|
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changeset
|
7024 <hr><h3><a name="pdf-xpcall"><code>xpcall (f, msgh [, arg1, ···])</code></a></h3> |
|
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changeset
|
7025 |
|
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parents:
diff
changeset
|
7026 |
|
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changeset
|
7027 <p> |
|
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changeset
|
7028 This function is similar to <a href="#pdf-pcall"><code>pcall</code></a>, |
|
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|
7029 except that it sets a new message handler <code>msgh</code>. |
|
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changeset
|
7030 |
|
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changeset
|
7031 |
|
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diff
changeset
|
7032 |
|
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diff
changeset
|
7033 |
|
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diff
changeset
|
7034 |
|
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changeset
|
7035 |
|
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diff
changeset
|
7036 |
|
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changeset
|
7037 <h2>6.2 – <a name="6.2">Coroutine Manipulation</a></h2> |
|
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parents:
diff
changeset
|
7038 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
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|
7039 <p> |
|
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parents:
diff
changeset
|
7040 The operations related to coroutines comprise a sub-library of |
|
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parents:
diff
changeset
|
7041 the basic library and come inside the table <a name="pdf-coroutine"><code>coroutine</code></a>. |
|
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parents:
diff
changeset
|
7042 See <a href="#2.6">§2.6</a> for a general description of coroutines. |
|
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parents:
diff
changeset
|
7043 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7044 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
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|
7045 <p> |
|
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parents:
diff
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|
7046 <hr><h3><a name="pdf-coroutine.create"><code>coroutine.create (f)</code></a></h3> |
|
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parents:
diff
changeset
|
7047 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7048 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7049 <p> |
|
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parents:
diff
changeset
|
7050 Creates a new coroutine, with body <code>f</code>. |
|
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parents:
diff
changeset
|
7051 <code>f</code> must be a Lua function. |
|
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parents:
diff
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|
7052 Returns this new coroutine, |
|
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parents:
diff
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|
7053 an object with type <code>"thread"</code>. |
|
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parents:
diff
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|
7054 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7055 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7056 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7057 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7058 <p> |
|
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parents:
diff
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|
7059 <hr><h3><a name="pdf-coroutine.isyieldable"><code>coroutine.isyieldable ()</code></a></h3> |
|
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parents:
diff
changeset
|
7060 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7061 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7062 <p> |
|
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parents:
diff
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|
7063 Returns true when the running coroutine can yield. |
|
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parents:
diff
changeset
|
7064 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7065 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7066 <p> |
|
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parents:
diff
changeset
|
7067 A running coroutine is yieldable if it is not the main thread and |
|
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parents:
diff
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|
7068 it is not inside a non-yieldable C function. |
|
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parents:
diff
changeset
|
7069 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7070 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7071 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7072 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
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|
7073 <p> |
|
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parents:
diff
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|
7074 <hr><h3><a name="pdf-coroutine.resume"><code>coroutine.resume (co [, val1, ···])</code></a></h3> |
|
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parents:
diff
changeset
|
7075 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7076 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
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|
7077 <p> |
|
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parents:
diff
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|
7078 Starts or continues the execution of coroutine <code>co</code>. |
|
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parents:
diff
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|
7079 The first time you resume a coroutine, |
|
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parents:
diff
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|
7080 it starts running its body. |
|
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parents:
diff
changeset
|
7081 The values <code>val1</code>, ... are passed |
|
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parents:
diff
changeset
|
7082 as the arguments to the body function. |
|
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parents:
diff
changeset
|
7083 If the coroutine has yielded, |
|
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parents:
diff
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|
7084 <code>resume</code> restarts it; |
|
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parents:
diff
changeset
|
7085 the values <code>val1</code>, ... are passed |
|
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parents:
diff
changeset
|
7086 as the results from the yield. |
|
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parents:
diff
changeset
|
7087 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7088 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7089 <p> |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7090 If the coroutine runs without any errors, |
|
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parents:
diff
changeset
|
7091 <code>resume</code> returns <b>true</b> plus any values passed to <code>yield</code> |
|
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parents:
diff
changeset
|
7092 (when the coroutine yields) or any values returned by the body function |
|
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parents:
diff
changeset
|
7093 (when the coroutine terminates). |
|
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parents:
diff
changeset
|
7094 If there is any error, |
|
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parents:
diff
changeset
|
7095 <code>resume</code> returns <b>false</b> plus the error message. |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7096 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7097 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7098 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7099 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7100 <p> |
|
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parents:
diff
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|
7101 <hr><h3><a name="pdf-coroutine.running"><code>coroutine.running ()</code></a></h3> |
|
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parents:
diff
changeset
|
7102 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7103 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7104 <p> |
|
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parents:
diff
changeset
|
7105 Returns the running coroutine plus a boolean, |
|
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parents:
diff
changeset
|
7106 true when the running coroutine is the main one. |
|
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parents:
diff
changeset
|
7107 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7108 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7109 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7110 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7111 <p> |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7112 <hr><h3><a name="pdf-coroutine.status"><code>coroutine.status (co)</code></a></h3> |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7113 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7114 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7115 <p> |
|
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parents:
diff
changeset
|
7116 Returns the status of coroutine <code>co</code>, as a string: |
|
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parents:
diff
changeset
|
7117 <code>"running"</code>, |
|
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parents:
diff
changeset
|
7118 if the coroutine is running (that is, it called <code>status</code>); |
|
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parents:
diff
changeset
|
7119 <code>"suspended"</code>, if the coroutine is suspended in a call to <code>yield</code>, |
|
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parents:
diff
changeset
|
7120 or if it has not started running yet; |
|
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parents:
diff
changeset
|
7121 <code>"normal"</code> if the coroutine is active but not running |
|
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parents:
diff
changeset
|
7122 (that is, it has resumed another coroutine); |
|
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parents:
diff
changeset
|
7123 and <code>"dead"</code> if the coroutine has finished its body function, |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7124 or if it has stopped with an error. |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7125 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7126 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7127 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7128 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7129 <p> |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7130 <hr><h3><a name="pdf-coroutine.wrap"><code>coroutine.wrap (f)</code></a></h3> |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7131 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7132 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7133 <p> |
|
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parents:
diff
changeset
|
7134 Creates a new coroutine, with body <code>f</code>. |
|
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parents:
diff
changeset
|
7135 <code>f</code> must be a Lua function. |
|
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parents:
diff
changeset
|
7136 Returns a function that resumes the coroutine each time it is called. |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7137 Any arguments passed to the function behave as the |
|
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parents:
diff
changeset
|
7138 extra arguments to <code>resume</code>. |
|
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parents:
diff
changeset
|
7139 Returns the same values returned by <code>resume</code>, |
|
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parents:
diff
changeset
|
7140 except the first boolean. |
|
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parents:
diff
changeset
|
7141 In case of error, propagates the error. |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7142 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7143 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7144 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7145 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7146 <p> |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7147 <hr><h3><a name="pdf-coroutine.yield"><code>coroutine.yield (···)</code></a></h3> |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7148 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7149 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7150 <p> |
|
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parents:
diff
changeset
|
7151 Suspends the execution of the calling coroutine. |
|
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parents:
diff
changeset
|
7152 Any arguments to <code>yield</code> are passed as extra results to <code>resume</code>. |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7153 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7154 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7155 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7156 |
|
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|
7157 |
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diff
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|
7158 |
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diff
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|
7159 |
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|
7160 <h2>6.3 – <a name="6.3">Modules</a></h2> |
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7161 |
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|
7162 <p> |
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|
7163 The package library provides basic |
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|
7164 facilities for loading modules in Lua. |
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7165 It exports one function directly in the global environment: |
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7166 <a href="#pdf-require"><code>require</code></a>. |
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7167 Everything else is exported in a table <a name="pdf-package"><code>package</code></a>. |
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7168 |
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|
7169 |
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7170 <p> |
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|
7171 <hr><h3><a name="pdf-require"><code>require (modname)</code></a></h3> |
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7172 |
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|
7173 |
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7174 <p> |
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|
7175 Loads the given module. |
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|
7176 The function starts by looking into the <a href="#pdf-package.loaded"><code>package.loaded</code></a> table |
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|
7177 to determine whether <code>modname</code> is already loaded. |
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7178 If it is, then <code>require</code> returns the value stored |
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7179 at <code>package.loaded[modname]</code>. |
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|
7180 Otherwise, it tries to find a <em>loader</em> for the module. |
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|
7181 |
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|
7182 |
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|
7183 <p> |
|
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|
7184 To find a loader, |
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7185 <code>require</code> is guided by the <a href="#pdf-package.searchers"><code>package.searchers</code></a> sequence. |
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7186 By changing this sequence, |
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7187 we can change how <code>require</code> looks for a module. |
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|
7188 The following explanation is based on the default configuration |
|
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|
7189 for <a href="#pdf-package.searchers"><code>package.searchers</code></a>. |
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|
7190 |
|
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|
7191 |
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|
7192 <p> |
|
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|
7193 First <code>require</code> queries <code>package.preload[modname]</code>. |
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7194 If it has a value, |
|
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|
7195 this value (which must be a function) is the loader. |
|
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|
7196 Otherwise <code>require</code> searches for a Lua loader using the |
|
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|
7197 path stored in <a href="#pdf-package.path"><code>package.path</code></a>. |
|
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|
7198 If that also fails, it searches for a C loader using the |
|
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|
7199 path stored in <a href="#pdf-package.cpath"><code>package.cpath</code></a>. |
|
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|
7200 If that also fails, |
|
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diff
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|
7201 it tries an <em>all-in-one</em> loader (see <a href="#pdf-package.searchers"><code>package.searchers</code></a>). |
|
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|
7202 |
|
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|
7203 |
|
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|
7204 <p> |
|
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|
7205 Once a loader is found, |
|
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|
7206 <code>require</code> calls the loader with two arguments: |
|
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|
7207 <code>modname</code> and an extra value dependent on how it got the loader. |
|
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|
7208 (If the loader came from a file, |
|
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|
7209 this extra value is the file name.) |
|
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|
7210 If the loader returns any non-nil value, |
|
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|
7211 <code>require</code> assigns the returned value to <code>package.loaded[modname]</code>. |
|
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|
7212 If the loader does not return a non-nil value and |
|
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|
7213 has not assigned any value to <code>package.loaded[modname]</code>, |
|
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|
7214 then <code>require</code> assigns <b>true</b> to this entry. |
|
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|
7215 In any case, <code>require</code> returns the |
|
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|
7216 final value of <code>package.loaded[modname]</code>. |
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|
7217 |
|
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|
7218 |
|
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|
7219 <p> |
|
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|
7220 If there is any error loading or running the module, |
|
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|
7221 or if it cannot find any loader for the module, |
|
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|
7222 then <code>require</code> raises an error. |
|
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|
7223 |
|
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diff
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|
7224 |
|
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|
7225 |
|
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|
7226 |
|
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|
7227 <p> |
|
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|
7228 <hr><h3><a name="pdf-package.config"><code>package.config</code></a></h3> |
|
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|
7229 |
|
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|
7230 |
|
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|
7231 <p> |
|
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|
7232 A string describing some compile-time configurations for packages. |
|
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|
7233 This string is a sequence of lines: |
|
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|
7234 |
|
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|
7235 <ul> |
|
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|
7236 |
|
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|
7237 <li>The first line is the directory separator string. |
|
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|
7238 Default is '<code>\</code>' for Windows and '<code>/</code>' for all other systems.</li> |
|
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|
7239 |
|
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diff
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|
7240 <li>The second line is the character that separates templates in a path. |
|
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|
7241 Default is '<code>;</code>'.</li> |
|
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|
7242 |
|
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|
7243 <li>The third line is the string that marks the |
|
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|
7244 substitution points in a template. |
|
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|
7245 Default is '<code>?</code>'.</li> |
|
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|
7246 |
|
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|
7247 <li>The fourth line is a string that, in a path in Windows, |
|
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|
7248 is replaced by the executable's directory. |
|
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|
7249 Default is '<code>!</code>'.</li> |
|
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|
7250 |
|
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|
7251 <li>The fifth line is a mark to ignore all text after it |
|
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|
7252 when building the <code>luaopen_</code> function name. |
|
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|
7253 Default is '<code>-</code>'.</li> |
|
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|
7254 |
|
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|
7255 </ul> |
|
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|
7256 |
|
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|
7257 |
|
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|
7258 |
|
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|
7259 <p> |
|
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|
7260 <hr><h3><a name="pdf-package.cpath"><code>package.cpath</code></a></h3> |
|
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|
7261 |
|
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|
7262 |
|
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|
7263 <p> |
|
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|
7264 The path used by <a href="#pdf-require"><code>require</code></a> to search for a C loader. |
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|
7265 |
|
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|
7266 |
|
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|
7267 <p> |
|
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|
7268 Lua initializes the C path <a href="#pdf-package.cpath"><code>package.cpath</code></a> in the same way |
|
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|
7269 it initializes the Lua path <a href="#pdf-package.path"><code>package.path</code></a>, |
|
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|
7270 using the environment variable <a name="pdf-LUA_CPATH_5_3"><code>LUA_CPATH_5_3</code></a> |
|
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|
7271 or the environment variable <a name="pdf-LUA_CPATH"><code>LUA_CPATH</code></a> |
|
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changeset
|
7272 or a default path defined in <code>luaconf.h</code>. |
|
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parents:
diff
changeset
|
7273 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7274 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7275 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7276 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
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|
7277 <p> |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7278 <hr><h3><a name="pdf-package.loaded"><code>package.loaded</code></a></h3> |
|
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add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7279 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7280 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7281 <p> |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7282 A table used by <a href="#pdf-require"><code>require</code></a> to control which |
|
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add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7283 modules are already loaded. |
|
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add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7284 When you require a module <code>modname</code> and |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7285 <code>package.loaded[modname]</code> is not false, |
|
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add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7286 <a href="#pdf-require"><code>require</code></a> simply returns the value stored there. |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7287 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7288 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7289 <p> |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7290 This variable is only a reference to the real table; |
|
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add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7291 assignments to this variable do not change the |
|
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add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7292 table used by <a href="#pdf-require"><code>require</code></a>. |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7293 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7294 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7295 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7296 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7297 <p> |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
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|
7298 <hr><h3><a name="pdf-package.loadlib"><code>package.loadlib (libname, funcname)</code></a></h3> |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7299 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7300 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7301 <p> |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7302 Dynamically links the host program with the C library <code>libname</code>. |
|
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parents:
diff
changeset
|
7303 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7304 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7305 <p> |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7306 If <code>funcname</code> is "<code>*</code>", |
|
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add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7307 then it only links with the library, |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7308 making the symbols exported by the library |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7309 available to other dynamically linked libraries. |
|
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parents:
diff
changeset
|
7310 Otherwise, |
|
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parents:
diff
changeset
|
7311 it looks for a function <code>funcname</code> inside the library |
|
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add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7312 and returns this function as a C function. |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7313 So, <code>funcname</code> must follow the <a href="#lua_CFunction"><code>lua_CFunction</code></a> prototype |
|
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parents:
diff
changeset
|
7314 (see <a href="#lua_CFunction"><code>lua_CFunction</code></a>). |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7315 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7316 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7317 <p> |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7318 This is a low-level function. |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7319 It completely bypasses the package and module system. |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7320 Unlike <a href="#pdf-require"><code>require</code></a>, |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7321 it does not perform any path searching and |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7322 does not automatically adds extensions. |
|
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parents:
diff
changeset
|
7323 <code>libname</code> must be the complete file name of the C library, |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7324 including if necessary a path and an extension. |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7325 <code>funcname</code> must be the exact name exported by the C library |
|
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add manual.html as copy of Lua 5.3 Reference Manual
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parents:
diff
changeset
|
7326 (which may depend on the C compiler and linker used). |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7327 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7328 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7329 <p> |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7330 This function is not supported by Standard C. |
|
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add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7331 As such, it is only available on some platforms |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7332 (Windows, Linux, Mac OS X, Solaris, BSD, |
|
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add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7333 plus other Unix systems that support the <code>dlfcn</code> standard). |
|
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add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7334 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7335 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7336 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7337 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7338 <p> |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7339 <hr><h3><a name="pdf-package.path"><code>package.path</code></a></h3> |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7340 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7341 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7342 <p> |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7343 The path used by <a href="#pdf-require"><code>require</code></a> to search for a Lua loader. |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7344 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7345 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7346 <p> |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7347 At start-up, Lua initializes this variable with |
|
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add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7348 the value of the environment variable <a name="pdf-LUA_PATH_5_3"><code>LUA_PATH_5_3</code></a> or |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7349 the environment variable <a name="pdf-LUA_PATH"><code>LUA_PATH</code></a> or |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7350 with a default path defined in <code>luaconf.h</code>, |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7351 if those environment variables are not defined. |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7352 Any "<code>;;</code>" in the value of the environment variable |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7353 is replaced by the default path. |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7354 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7355 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7356 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7357 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7358 <p> |
|
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add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7359 <hr><h3><a name="pdf-package.preload"><code>package.preload</code></a></h3> |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7360 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7361 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7362 <p> |
|
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parents:
diff
changeset
|
7363 A table to store loaders for specific modules |
|
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parents:
diff
changeset
|
7364 (see <a href="#pdf-require"><code>require</code></a>). |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7365 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7366 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7367 <p> |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7368 This variable is only a reference to the real table; |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7369 assignments to this variable do not change the |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7370 table used by <a href="#pdf-require"><code>require</code></a>. |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7371 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7372 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7373 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7374 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7375 <p> |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7376 <hr><h3><a name="pdf-package.searchers"><code>package.searchers</code></a></h3> |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7377 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7378 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7379 <p> |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7380 A table used by <a href="#pdf-require"><code>require</code></a> to control how to load modules. |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7381 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7382 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7383 <p> |
|
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parents:
diff
changeset
|
7384 Each entry in this table is a <em>searcher function</em>. |
|
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parents:
diff
changeset
|
7385 When looking for a module, |
|
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parents:
diff
changeset
|
7386 <a href="#pdf-require"><code>require</code></a> calls each of these searchers in ascending order, |
|
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diff
changeset
|
7387 with the module name (the argument given to <a href="#pdf-require"><code>require</code></a>) as its |
|
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parents:
diff
changeset
|
7388 sole parameter. |
|
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parents:
diff
changeset
|
7389 The function can return another function (the module <em>loader</em>) |
|
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parents:
diff
changeset
|
7390 plus an extra value that will be passed to that loader, |
|
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add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7391 or a string explaining why it did not find that module |
|
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add manual.html as copy of Lua 5.3 Reference Manual
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parents:
diff
changeset
|
7392 (or <b>nil</b> if it has nothing to say). |
|
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add manual.html as copy of Lua 5.3 Reference Manual
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parents:
diff
changeset
|
7393 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7394 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7395 <p> |
|
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add manual.html as copy of Lua 5.3 Reference Manual
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parents:
diff
changeset
|
7396 Lua initializes this table with four searcher functions. |
|
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add manual.html as copy of Lua 5.3 Reference Manual
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parents:
diff
changeset
|
7397 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7398 |
|
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add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7399 <p> |
|
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add manual.html as copy of Lua 5.3 Reference Manual
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parents:
diff
changeset
|
7400 The first searcher simply looks for a loader in the |
|
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add manual.html as copy of Lua 5.3 Reference Manual
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parents:
diff
changeset
|
7401 <a href="#pdf-package.preload"><code>package.preload</code></a> table. |
|
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add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7402 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7403 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7404 <p> |
|
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add manual.html as copy of Lua 5.3 Reference Manual
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parents:
diff
changeset
|
7405 The second searcher looks for a loader as a Lua library, |
|
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add manual.html as copy of Lua 5.3 Reference Manual
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parents:
diff
changeset
|
7406 using the path stored at <a href="#pdf-package.path"><code>package.path</code></a>. |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7407 The search is done as described in function <a href="#pdf-package.searchpath"><code>package.searchpath</code></a>. |
|
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add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7408 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7409 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7410 <p> |
|
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add manual.html as copy of Lua 5.3 Reference Manual
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parents:
diff
changeset
|
7411 The third searcher looks for a loader as a C library, |
|
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add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7412 using the path given by the variable <a href="#pdf-package.cpath"><code>package.cpath</code></a>. |
|
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add manual.html as copy of Lua 5.3 Reference Manual
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parents:
diff
changeset
|
7413 Again, |
|
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add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7414 the search is done as described in function <a href="#pdf-package.searchpath"><code>package.searchpath</code></a>. |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7415 For instance, |
|
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add manual.html as copy of Lua 5.3 Reference Manual
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parents:
diff
changeset
|
7416 if the C path is the string |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7417 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7418 <pre> |
|
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add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7419 "./?.so;./?.dll;/usr/local/?/init.so" |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7420 </pre><p> |
|
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parents:
diff
changeset
|
7421 the searcher for module <code>foo</code> |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
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parents:
diff
changeset
|
7422 will try to open the files <code>./foo.so</code>, <code>./foo.dll</code>, |
|
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add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7423 and <code>/usr/local/foo/init.so</code>, in that order. |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7424 Once it finds a C library, |
|
e01cddba3433
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parents:
diff
changeset
|
7425 this searcher first uses a dynamic link facility to link the |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
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parents:
diff
changeset
|
7426 application with the library. |
|
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add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7427 Then it tries to find a C function inside the library to |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7428 be used as the loader. |
|
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add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7429 The name of this C function is the string "<code>luaopen_</code>" |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7430 concatenated with a copy of the module name where each dot |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7431 is replaced by an underscore. |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7432 Moreover, if the module name has a hyphen, |
|
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add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7433 its suffix after (and including) the first hyphen is removed. |
|
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add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7434 For instance, if the module name is <code>a.b.c-v2.1</code>, |
|
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add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7435 the function name will be <code>luaopen_a_b_c</code>. |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7436 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7437 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7438 <p> |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7439 The fourth searcher tries an <em>all-in-one loader</em>. |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7440 It searches the C path for a library for |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7441 the root name of the given module. |
|
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add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7442 For instance, when requiring <code>a.b.c</code>, |
|
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add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7443 it will search for a C library for <code>a</code>. |
|
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add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7444 If found, it looks into it for an open function for |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7445 the submodule; |
|
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add manual.html as copy of Lua 5.3 Reference Manual
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parents:
diff
changeset
|
7446 in our example, that would be <code>luaopen_a_b_c</code>. |
|
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add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7447 With this facility, a package can pack several C submodules |
|
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add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7448 into one single library, |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7449 with each submodule keeping its original open function. |
|
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add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7450 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7451 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7452 <p> |
|
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add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7453 All searchers except the first one (preload) return as the extra value |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7454 the file name where the module was found, |
|
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add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7455 as returned by <a href="#pdf-package.searchpath"><code>package.searchpath</code></a>. |
|
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add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7456 The first searcher returns no extra value. |
|
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add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7457 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7458 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7459 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7460 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7461 <p> |
|
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add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7462 <hr><h3><a name="pdf-package.searchpath"><code>package.searchpath (name, path [, sep [, rep]])</code></a></h3> |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7463 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7464 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7465 <p> |
|
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add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7466 Searches for the given <code>name</code> in the given <code>path</code>. |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7467 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7468 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7469 <p> |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7470 A path is a string containing a sequence of |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7471 <em>templates</em> separated by semicolons. |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7472 For each template, |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7473 the function replaces each interrogation mark (if any) |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7474 in the template with a copy of <code>name</code> |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7475 wherein all occurrences of <code>sep</code> |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7476 (a dot, by default) |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7477 were replaced by <code>rep</code> |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7478 (the system's directory separator, by default), |
|
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add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7479 and then tries to open the resulting file name. |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7480 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7481 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7482 <p> |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7483 For instance, if the path is the string |
|
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add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7484 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7485 <pre> |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7486 "./?.lua;./?.lc;/usr/local/?/init.lua" |
|
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parents:
diff
changeset
|
7487 </pre><p> |
|
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parents:
diff
changeset
|
7488 the search for the name <code>foo.a</code> |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7489 will try to open the files |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7490 <code>./foo/a.lua</code>, <code>./foo/a.lc</code>, and |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7491 <code>/usr/local/foo/a/init.lua</code>, in that order. |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7492 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7493 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7494 <p> |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7495 Returns the resulting name of the first file that it can |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7496 open in read mode (after closing the file), |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7497 or <b>nil</b> plus an error message if none succeeds. |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7498 (This error message lists all file names it tried to open.) |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7499 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7500 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7501 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7502 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7503 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7504 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7505 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7506 <h2>6.4 – <a name="6.4">String Manipulation</a></h2> |
|
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diff
changeset
|
7507 |
|
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7508 <p> |
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|
7509 This library provides generic functions for string manipulation, |
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7510 such as finding and extracting substrings, and pattern matching. |
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7511 When indexing a string in Lua, the first character is at position 1 |
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7512 (not at 0, as in C). |
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7513 Indices are allowed to be negative and are interpreted as indexing backwards, |
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7514 from the end of the string. |
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7515 Thus, the last character is at position -1, and so on. |
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7516 |
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7517 |
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|
7518 <p> |
|
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7519 The string library provides all its functions inside the table |
|
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7520 <a name="pdf-string"><code>string</code></a>. |
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7521 It also sets a metatable for strings |
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7522 where the <code>__index</code> field points to the <code>string</code> table. |
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7523 Therefore, you can use the string functions in object-oriented style. |
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7524 For instance, <code>string.byte(s,i)</code> |
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7525 can be written as <code>s:byte(i)</code>. |
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7526 |
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7527 |
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7528 <p> |
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7529 The string library assumes one-byte character encodings. |
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7530 |
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7531 |
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7532 <p> |
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|
7533 <hr><h3><a name="pdf-string.byte"><code>string.byte (s [, i [, j]])</code></a></h3> |
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7534 Returns the internal numerical codes of the characters <code>s[i]</code>, |
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7535 <code>s[i+1]</code>, ..., <code>s[j]</code>. |
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7536 The default value for <code>i</code> is 1; |
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7537 the default value for <code>j</code> is <code>i</code>. |
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7538 These indices are corrected |
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7539 following the same rules of function <a href="#pdf-string.sub"><code>string.sub</code></a>. |
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7540 |
|
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7541 |
|
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7542 <p> |
|
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|
7543 Numerical codes are not necessarily portable across platforms. |
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7544 |
|
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7545 |
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7546 |
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|
7547 |
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7548 <p> |
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|
7549 <hr><h3><a name="pdf-string.char"><code>string.char (···)</code></a></h3> |
|
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7550 Receives zero or more integers. |
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7551 Returns a string with length equal to the number of arguments, |
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7552 in which each character has the internal numerical code equal |
|
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7553 to its corresponding argument. |
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7554 |
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|
7555 |
|
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|
7556 <p> |
|
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|
7557 Numerical codes are not necessarily portable across platforms. |
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|
7558 |
|
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|
7559 |
|
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|
7560 |
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|
7561 |
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7562 <p> |
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|
7563 <hr><h3><a name="pdf-string.dump"><code>string.dump (function [, strip])</code></a></h3> |
|
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|
7564 |
|
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|
7565 |
|
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|
7566 <p> |
|
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|
7567 Returns a string containing a binary representation |
|
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|
7568 (a <em>binary chunk</em>) |
|
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7569 of the given function, |
|
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|
7570 so that a later <a href="#pdf-load"><code>load</code></a> on this string returns |
|
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7571 a copy of the function (but with new upvalues). |
|
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|
7572 If <code>strip</code> is a true value, |
|
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|
7573 the binary representation is created without debug information |
|
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7574 about the function |
|
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|
7575 (local variable names, lines, etc.). |
|
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|
7576 |
|
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|
7577 |
|
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|
7578 <p> |
|
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|
7579 Functions with upvalues have only their number of upvalues saved. |
|
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|
7580 When (re)loaded, |
|
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|
7581 those upvalues receive fresh instances containing <b>nil</b>. |
|
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|
7582 (You can use the debug library to serialize |
|
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|
7583 and reload the upvalues of a function |
|
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|
7584 in a way adequate to your needs.) |
|
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|
7585 |
|
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|
7586 |
|
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|
7587 |
|
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|
7588 |
|
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|
7589 <p> |
|
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|
7590 <hr><h3><a name="pdf-string.find"><code>string.find (s, pattern [, init [, plain]])</code></a></h3> |
|
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|
7591 |
|
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|
7592 |
|
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|
7593 <p> |
|
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|
7594 Looks for the first match of |
|
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|
7595 <code>pattern</code> (see <a href="#6.4.1">§6.4.1</a>) in the string <code>s</code>. |
|
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|
7596 If it finds a match, then <code>find</code> returns the indices of <code>s</code> |
|
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7597 where this occurrence starts and ends; |
|
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|
7598 otherwise, it returns <b>nil</b>. |
|
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|
7599 A third, optional numerical argument <code>init</code> specifies |
|
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|
7600 where to start the search; |
|
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|
7601 its default value is 1 and can be negative. |
|
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|
7602 A value of <b>true</b> as a fourth, optional argument <code>plain</code> |
|
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|
7603 turns off the pattern matching facilities, |
|
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|
7604 so the function does a plain "find substring" operation, |
|
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|
7605 with no characters in <code>pattern</code> being considered magic. |
|
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|
7606 Note that if <code>plain</code> is given, then <code>init</code> must be given as well. |
|
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|
7607 |
|
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|
7608 |
|
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|
7609 <p> |
|
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|
7610 If the pattern has captures, |
|
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|
7611 then in a successful match |
|
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|
7612 the captured values are also returned, |
|
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|
7613 after the two indices. |
|
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|
7614 |
|
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|
7615 |
|
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|
7616 |
|
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|
7617 |
|
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|
7618 <p> |
|
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|
7619 <hr><h3><a name="pdf-string.format"><code>string.format (formatstring, ···)</code></a></h3> |
|
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|
7620 |
|
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|
7621 |
|
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|
7622 <p> |
|
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|
7623 Returns a formatted version of its variable number of arguments |
|
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|
7624 following the description given in its first argument (which must be a string). |
|
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|
7625 The format string follows the same rules as the ISO C function <code>sprintf</code>. |
|
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7626 The only differences are that the options/modifiers |
|
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|
7627 <code>*</code>, <code>h</code>, <code>L</code>, <code>l</code>, <code>n</code>, |
|
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|
7628 and <code>p</code> are not supported |
|
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|
7629 and that there is an extra option, <code>q</code>. |
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|
7630 The <code>q</code> option formats a string between double quotes, |
|
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|
7631 using escape sequences when necessary to ensure that |
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|
7632 it can safely be read back by the Lua interpreter. |
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|
7633 For instance, the call |
|
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|
7634 |
|
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|
7635 <pre> |
|
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|
7636 string.format('%q', 'a string with "quotes" and \n new line') |
|
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7637 </pre><p> |
|
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|
7638 may produce the string: |
|
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|
7639 |
|
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|
7640 <pre> |
|
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|
7641 "a string with \"quotes\" and \ |
|
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|
7642 new line" |
|
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|
7643 </pre> |
|
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|
7644 |
|
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|
7645 <p> |
|
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|
7646 Options |
|
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|
7647 <code>A</code> and <code>a</code> (when available), |
|
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|
7648 <code>E</code>, <code>e</code>, <code>f</code>, |
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|
7649 <code>G</code>, and <code>g</code> all expect a number as argument. |
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7650 Options <code>c</code>, <code>d</code>, |
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|
7651 <code>i</code>, <code>o</code>, <code>u</code>, <code>X</code>, and <code>x</code> |
|
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7652 expect an integer. |
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|
7653 Option <code>q</code> expects a string; |
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7654 option <code>s</code> expects a string without embedded zeros. |
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|
7655 If the argument to option <code>s</code> is not a string, |
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|
7656 it is converted to one following the same rules of <a href="#pdf-tostring"><code>tostring</code></a>. |
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|
7657 |
|
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|
7658 |
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|
7659 |
|
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|
7660 |
|
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|
7661 <p> |
|
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|
7662 <hr><h3><a name="pdf-string.gmatch"><code>string.gmatch (s, pattern)</code></a></h3> |
|
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|
7663 Returns an iterator function that, |
|
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|
7664 each time it is called, |
|
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|
7665 returns the next captures from <code>pattern</code> (see <a href="#6.4.1">§6.4.1</a>) |
|
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|
7666 over the string <code>s</code>. |
|
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|
7667 If <code>pattern</code> specifies no captures, |
|
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|
7668 then the whole match is produced in each call. |
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|
7669 |
|
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|
7670 |
|
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|
7671 <p> |
|
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|
7672 As an example, the following loop |
|
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|
7673 will iterate over all the words from string <code>s</code>, |
|
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|
7674 printing one per line: |
|
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|
7675 |
|
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|
7676 <pre> |
|
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|
7677 s = "hello world from Lua" |
|
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|
7678 for w in string.gmatch(s, "%a+") do |
|
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|
7679 print(w) |
|
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|
7680 end |
|
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|
7681 </pre><p> |
|
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|
7682 The next example collects all pairs <code>key=value</code> from the |
|
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|
7683 given string into a table: |
|
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|
7684 |
|
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|
7685 <pre> |
|
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|
7686 t = {} |
|
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|
7687 s = "from=world, to=Lua" |
|
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|
7688 for k, v in string.gmatch(s, "(%w+)=(%w+)") do |
|
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|
7689 t[k] = v |
|
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|
7690 end |
|
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|
7691 </pre> |
|
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|
7692 |
|
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|
7693 <p> |
|
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|
7694 For this function, a caret '<code>^</code>' at the start of a pattern does not |
|
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|
7695 work as an anchor, as this would prevent the iteration. |
|
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|
7696 |
|
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|
7697 |
|
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|
7698 |
|
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|
7699 |
|
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|
7700 <p> |
|
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|
7701 <hr><h3><a name="pdf-string.gsub"><code>string.gsub (s, pattern, repl [, n])</code></a></h3> |
|
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|
7702 Returns a copy of <code>s</code> |
|
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|
7703 in which all (or the first <code>n</code>, if given) |
|
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|
7704 occurrences of the <code>pattern</code> (see <a href="#6.4.1">§6.4.1</a>) have been |
|
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|
7705 replaced by a replacement string specified by <code>repl</code>, |
|
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|
7706 which can be a string, a table, or a function. |
|
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|
7707 <code>gsub</code> also returns, as its second value, |
|
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|
7708 the total number of matches that occurred. |
|
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|
7709 The name <code>gsub</code> comes from <em>Global SUBstitution</em>. |
|
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|
7710 |
|
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|
7711 |
|
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|
7712 <p> |
|
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|
7713 If <code>repl</code> is a string, then its value is used for replacement. |
|
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|
7714 The character <code>%</code> works as an escape character: |
|
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|
7715 any sequence in <code>repl</code> of the form <code>%<em>d</em></code>, |
|
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|
7716 with <em>d</em> between 1 and 9, |
|
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|
7717 stands for the value of the <em>d</em>-th captured substring. |
|
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7718 The sequence <code>%0</code> stands for the whole match. |
|
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|
7719 The sequence <code>%%</code> stands for a single <code>%</code>. |
|
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|
7720 |
|
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|
7721 |
|
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|
7722 <p> |
|
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|
7723 If <code>repl</code> is a table, then the table is queried for every match, |
|
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|
7724 using the first capture as the key. |
|
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|
7725 |
|
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|
7726 |
|
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|
7727 <p> |
|
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|
7728 If <code>repl</code> is a function, then this function is called every time a |
|
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|
7729 match occurs, with all captured substrings passed as arguments, |
|
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|
7730 in order. |
|
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|
7731 |
|
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|
7732 |
|
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|
7733 <p> |
|
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|
7734 In any case, |
|
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|
7735 if the pattern specifies no captures, |
|
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|
7736 then it behaves as if the whole pattern was inside a capture. |
|
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|
7737 |
|
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|
7738 |
|
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|
7739 <p> |
|
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|
7740 If the value returned by the table query or by the function call |
|
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changeset
|
7741 is a string or a number, |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7742 then it is used as the replacement string; |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7743 otherwise, if it is <b>false</b> or <b>nil</b>, |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7744 then there is no replacement |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7745 (that is, the original match is kept in the string). |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7746 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7747 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7748 <p> |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7749 Here are some examples: |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7750 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7751 <pre> |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7752 x = string.gsub("hello world", "(%w+)", "%1 %1") |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7753 --> x="hello hello world world" |
|
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add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7754 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7755 x = string.gsub("hello world", "%w+", "%0 %0", 1) |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7756 --> x="hello hello world" |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7757 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7758 x = string.gsub("hello world from Lua", "(%w+)%s*(%w+)", "%2 %1") |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7759 --> x="world hello Lua from" |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7760 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7761 x = string.gsub("home = $HOME, user = $USER", "%$(%w+)", os.getenv) |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7762 --> x="home = /home/roberto, user = roberto" |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7763 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7764 x = string.gsub("4+5 = $return 4+5$", "%$(.-)%$", function (s) |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7765 return load(s)() |
|
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add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7766 end) |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7767 --> x="4+5 = 9" |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7768 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7769 local t = {name="lua", version="5.3"} |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7770 x = string.gsub("$name-$version.tar.gz", "%$(%w+)", t) |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7771 --> x="lua-5.3.tar.gz" |
|
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add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7772 </pre> |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7773 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7774 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7775 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7776 <p> |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7777 <hr><h3><a name="pdf-string.len"><code>string.len (s)</code></a></h3> |
|
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add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7778 Receives a string and returns its length. |
|
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add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7779 The empty string <code>""</code> has length 0. |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7780 Embedded zeros are counted, |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7781 so <code>"a\000bc\000"</code> has length 5. |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7782 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7783 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7784 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7785 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7786 <p> |
|
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add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7787 <hr><h3><a name="pdf-string.lower"><code>string.lower (s)</code></a></h3> |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7788 Receives a string and returns a copy of this string with all |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7789 uppercase letters changed to lowercase. |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7790 All other characters are left unchanged. |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7791 The definition of what an uppercase letter is depends on the current locale. |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7792 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7793 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7794 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7795 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7796 <p> |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7797 <hr><h3><a name="pdf-string.match"><code>string.match (s, pattern [, init])</code></a></h3> |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7798 Looks for the first <em>match</em> of |
|
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add manual.html as copy of Lua 5.3 Reference Manual
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parents:
diff
changeset
|
7799 <code>pattern</code> (see <a href="#6.4.1">§6.4.1</a>) in the string <code>s</code>. |
|
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add manual.html as copy of Lua 5.3 Reference Manual
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parents:
diff
changeset
|
7800 If it finds one, then <code>match</code> returns |
|
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add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7801 the captures from the pattern; |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7802 otherwise it returns <b>nil</b>. |
|
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add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7803 If <code>pattern</code> specifies no captures, |
|
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add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7804 then the whole match is returned. |
|
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add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7805 A third, optional numerical argument <code>init</code> specifies |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7806 where to start the search; |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7807 its default value is 1 and can be negative. |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7808 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7809 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7810 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7811 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7812 <p> |
|
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add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7813 <hr><h3><a name="pdf-string.pack"><code>string.pack (fmt, v1, v2, ···)</code></a></h3> |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7814 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7815 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7816 <p> |
|
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add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7817 Returns a binary string containing the values <code>v1</code>, <code>v2</code>, etc. |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7818 packed (that is, serialized in binary form) |
|
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add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7819 according to the format string <code>fmt</code> (see <a href="#6.4.2">§6.4.2</a>). |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7820 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7821 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7822 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7823 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7824 <p> |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7825 <hr><h3><a name="pdf-string.packsize"><code>string.packsize (fmt)</code></a></h3> |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7826 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7827 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7828 <p> |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7829 Returns the size of a string resulting from <a href="#pdf-string.pack"><code>string.pack</code></a> |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7830 with the given format. |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7831 The format string cannot have the variable-length options |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7832 '<code>s</code>' or '<code>z</code>' (see <a href="#6.4.2">§6.4.2</a>). |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7833 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7834 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7835 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7836 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7837 <p> |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7838 <hr><h3><a name="pdf-string.rep"><code>string.rep (s, n [, sep])</code></a></h3> |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7839 Returns a string that is the concatenation of <code>n</code> copies of |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7840 the string <code>s</code> separated by the string <code>sep</code>. |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7841 The default value for <code>sep</code> is the empty string |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7842 (that is, no separator). |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7843 Returns the empty string if <code>n</code> is not positive. |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7844 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7845 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7846 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7847 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7848 <p> |
|
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add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7849 <hr><h3><a name="pdf-string.reverse"><code>string.reverse (s)</code></a></h3> |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
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parents:
diff
changeset
|
7850 Returns a string that is the string <code>s</code> reversed. |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7851 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7852 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7853 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7854 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7855 <p> |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
7856 <hr><h3><a name="pdf-string.sub"><code>string.sub (s, i [, j])</code></a></h3> |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
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parents:
diff
changeset
|
7857 Returns the substring of <code>s</code> that |
|
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7858 starts at <code>i</code> and continues until <code>j</code>; |
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7859 <code>i</code> and <code>j</code> can be negative. |
|
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7860 If <code>j</code> is absent, then it is assumed to be equal to -1 |
|
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7861 (which is the same as the string length). |
|
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7862 In particular, |
|
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|
7863 the call <code>string.sub(s,1,j)</code> returns a prefix of <code>s</code> |
|
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7864 with length <code>j</code>, |
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|
7865 and <code>string.sub(s, -i)</code> returns a suffix of <code>s</code> |
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7866 with length <code>i</code>. |
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7867 |
|
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|
7868 |
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|
7869 <p> |
|
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|
7870 If, after the translation of negative indices, |
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7871 <code>i</code> is less than 1, |
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7872 it is corrected to 1. |
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7873 If <code>j</code> is greater than the string length, |
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7874 it is corrected to that length. |
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7875 If, after these corrections, |
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7876 <code>i</code> is greater than <code>j</code>, |
|
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7877 the function returns the empty string. |
|
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|
7878 |
|
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|
7879 |
|
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|
7880 |
|
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|
7881 |
|
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|
7882 <p> |
|
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|
7883 <hr><h3><a name="pdf-string.unpack"><code>string.unpack (fmt, s [, pos])</code></a></h3> |
|
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|
7884 |
|
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|
7885 |
|
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|
7886 <p> |
|
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|
7887 Returns the values packed in string <code>s</code> (see <a href="#pdf-string.pack"><code>string.pack</code></a>) |
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7888 according to the format string <code>fmt</code> (see <a href="#6.4.2">§6.4.2</a>). |
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7889 An optional <code>pos</code> marks where |
|
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|
7890 to start reading in <code>s</code> (default is 1). |
|
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7891 After the read values, |
|
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|
7892 this function also returns the index of the first unread byte in <code>s</code>. |
|
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|
7893 |
|
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|
7894 |
|
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|
7895 |
|
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|
7896 |
|
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|
7897 <p> |
|
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|
7898 <hr><h3><a name="pdf-string.upper"><code>string.upper (s)</code></a></h3> |
|
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7899 Receives a string and returns a copy of this string with all |
|
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7900 lowercase letters changed to uppercase. |
|
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7901 All other characters are left unchanged. |
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7902 The definition of what a lowercase letter is depends on the current locale. |
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|
7903 |
|
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|
7904 |
|
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|
7905 |
|
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|
7906 |
|
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|
7907 |
|
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|
7908 <h3>6.4.1 – <a name="6.4.1">Patterns</a></h3> |
|
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7909 |
|
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|
7910 <p> |
|
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7911 Patterns in Lua are described by regular strings, |
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|
7912 which are interpreted as patterns by the pattern-matching functions |
|
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|
7913 <a href="#pdf-string.find"><code>string.find</code></a>, |
|
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|
7914 <a href="#pdf-string.gmatch"><code>string.gmatch</code></a>, |
|
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|
7915 <a href="#pdf-string.gsub"><code>string.gsub</code></a>, |
|
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|
7916 and <a href="#pdf-string.match"><code>string.match</code></a>. |
|
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7917 This section describes the syntax and the meaning |
|
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7918 (that is, what they match) of these strings. |
|
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|
7919 |
|
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|
7920 |
|
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|
7921 |
|
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|
7922 <h4>Character Class:</h4><p> |
|
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|
7923 A <em>character class</em> is used to represent a set of characters. |
|
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7924 The following combinations are allowed in describing a character class: |
|
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|
7925 |
|
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|
7926 <ul> |
|
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|
7927 |
|
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7928 <li><b><em>x</em>: </b> |
|
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|
7929 (where <em>x</em> is not one of the <em>magic characters</em> |
|
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7930 <code>^$()%.[]*+-?</code>) |
|
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|
7931 represents the character <em>x</em> itself. |
|
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|
7932 </li> |
|
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|
7933 |
|
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|
7934 <li><b><code>.</code>: </b> (a dot) represents all characters.</li> |
|
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|
7935 |
|
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|
7936 <li><b><code>%a</code>: </b> represents all letters.</li> |
|
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|
7937 |
|
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|
7938 <li><b><code>%c</code>: </b> represents all control characters.</li> |
|
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|
7939 |
|
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|
7940 <li><b><code>%d</code>: </b> represents all digits.</li> |
|
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|
7941 |
|
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|
7942 <li><b><code>%g</code>: </b> represents all printable characters except space.</li> |
|
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|
7943 |
|
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|
7944 <li><b><code>%l</code>: </b> represents all lowercase letters.</li> |
|
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|
7945 |
|
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|
7946 <li><b><code>%p</code>: </b> represents all punctuation characters.</li> |
|
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|
7947 |
|
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|
7948 <li><b><code>%s</code>: </b> represents all space characters.</li> |
|
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|
7949 |
|
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|
7950 <li><b><code>%u</code>: </b> represents all uppercase letters.</li> |
|
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|
7951 |
|
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|
7952 <li><b><code>%w</code>: </b> represents all alphanumeric characters.</li> |
|
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7953 |
|
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|
7954 <li><b><code>%x</code>: </b> represents all hexadecimal digits.</li> |
|
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7955 |
|
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|
7956 <li><b><code>%<em>x</em></code>: </b> (where <em>x</em> is any non-alphanumeric character) |
|
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|
7957 represents the character <em>x</em>. |
|
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7958 This is the standard way to escape the magic characters. |
|
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|
7959 Any non-alphanumeric character |
|
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|
7960 (including all punctuations, even the non-magical) |
|
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7961 can be preceded by a '<code>%</code>' |
|
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|
7962 when used to represent itself in a pattern. |
|
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|
7963 </li> |
|
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|
7964 |
|
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|
7965 <li><b><code>[<em>set</em>]</code>: </b> |
|
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7966 represents the class which is the union of all |
|
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|
7967 characters in <em>set</em>. |
|
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7968 A range of characters can be specified by |
|
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|
7969 separating the end characters of the range, |
|
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7970 in ascending order, with a '<code>-</code>'. |
|
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7971 All classes <code>%</code><em>x</em> described above can also be used as |
|
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|
7972 components in <em>set</em>. |
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|
7973 All other characters in <em>set</em> represent themselves. |
|
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|
7974 For example, <code>[%w_]</code> (or <code>[_%w]</code>) |
|
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7975 represents all alphanumeric characters plus the underscore, |
|
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|
7976 <code>[0-7]</code> represents the octal digits, |
|
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|
7977 and <code>[0-7%l%-]</code> represents the octal digits plus |
|
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|
7978 the lowercase letters plus the '<code>-</code>' character. |
|
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|
7979 |
|
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|
7980 |
|
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|
7981 <p> |
|
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|
7982 The interaction between ranges and classes is not defined. |
|
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|
7983 Therefore, patterns like <code>[%a-z]</code> or <code>[a-%%]</code> |
|
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|
7984 have no meaning. |
|
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|
7985 </li> |
|
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|
7986 |
|
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|
7987 <li><b><code>[^<em>set</em>]</code>: </b> |
|
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|
7988 represents the complement of <em>set</em>, |
|
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|
7989 where <em>set</em> is interpreted as above. |
|
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|
7990 </li> |
|
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|
7991 |
|
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|
7992 </ul><p> |
|
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|
7993 For all classes represented by single letters (<code>%a</code>, <code>%c</code>, etc.), |
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7994 the corresponding uppercase letter represents the complement of the class. |
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|
7995 For instance, <code>%S</code> represents all non-space characters. |
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7996 |
|
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|
7997 |
|
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|
7998 <p> |
|
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7999 The definitions of letter, space, and other character groups |
|
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8000 depend on the current locale. |
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|
8001 In particular, the class <code>[a-z]</code> may not be equivalent to <code>%l</code>. |
|
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|
8002 |
|
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|
8003 |
|
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|
8004 |
|
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|
8005 |
|
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|
8006 |
|
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|
8007 <h4>Pattern Item:</h4><p> |
|
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|
8008 A <em>pattern item</em> can be |
|
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|
8009 |
|
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|
8010 <ul> |
|
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|
8011 |
|
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|
8012 <li> |
|
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|
8013 a single character class, |
|
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|
8014 which matches any single character in the class; |
|
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|
8015 </li> |
|
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|
8016 |
|
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|
8017 <li> |
|
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|
8018 a single character class followed by '<code>*</code>', |
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|
8019 which matches zero or more repetitions of characters in the class. |
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|
8020 These repetition items will always match the longest possible sequence; |
|
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|
8021 </li> |
|
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|
8022 |
|
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|
8023 <li> |
|
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|
8024 a single character class followed by '<code>+</code>', |
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|
8025 which matches one or more repetitions of characters in the class. |
|
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|
8026 These repetition items will always match the longest possible sequence; |
|
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|
8027 </li> |
|
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|
8028 |
|
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|
8029 <li> |
|
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|
8030 a single character class followed by '<code>-</code>', |
|
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|
8031 which also matches zero or more repetitions of characters in the class. |
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|
8032 Unlike '<code>*</code>', |
|
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|
8033 these repetition items will always match the shortest possible sequence; |
|
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|
8034 </li> |
|
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|
8035 |
|
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|
8036 <li> |
|
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|
8037 a single character class followed by '<code>?</code>', |
|
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8038 which matches zero or one occurrence of a character in the class. |
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|
8039 It always matches one occurrence if possible; |
|
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|
8040 </li> |
|
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|
8041 |
|
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|
8042 <li> |
|
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|
8043 <code>%<em>n</em></code>, for <em>n</em> between 1 and 9; |
|
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|
8044 such item matches a substring equal to the <em>n</em>-th captured string |
|
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|
8045 (see below); |
|
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|
8046 </li> |
|
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|
8047 |
|
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|
8048 <li> |
|
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|
8049 <code>%b<em>xy</em></code>, where <em>x</em> and <em>y</em> are two distinct characters; |
|
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|
8050 such item matches strings that start with <em>x</em>, end with <em>y</em>, |
|
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|
8051 and where the <em>x</em> and <em>y</em> are <em>balanced</em>. |
|
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|
8052 This means that, if one reads the string from left to right, |
|
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|
8053 counting <em>+1</em> for an <em>x</em> and <em>-1</em> for a <em>y</em>, |
|
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|
8054 the ending <em>y</em> is the first <em>y</em> where the count reaches 0. |
|
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|
8055 For instance, the item <code>%b()</code> matches expressions with |
|
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|
8056 balanced parentheses. |
|
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|
8057 </li> |
|
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|
8058 |
|
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|
8059 <li> |
|
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|
8060 <code>%f[<em>set</em>]</code>, a <em>frontier pattern</em>; |
|
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|
8061 such item matches an empty string at any position such that |
|
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8062 the next character belongs to <em>set</em> |
|
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8063 and the previous character does not belong to <em>set</em>. |
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|
8064 The set <em>set</em> is interpreted as previously described. |
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|
8065 The beginning and the end of the subject are handled as if |
|
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|
8066 they were the character '<code>\0</code>'. |
|
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|
8067 </li> |
|
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changeset
|
8068 |
|
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|
8069 </ul> |
|
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|
8070 |
|
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|
8071 |
|
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|
8072 |
|
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|
8073 |
|
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|
8074 <h4>Pattern:</h4><p> |
|
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|
8075 A <em>pattern</em> is a sequence of pattern items. |
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|
8076 A caret '<code>^</code>' at the beginning of a pattern anchors the match at the |
|
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|
8077 beginning of the subject string. |
|
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|
8078 A '<code>$</code>' at the end of a pattern anchors the match at the |
|
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|
8079 end of the subject string. |
|
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8080 At other positions, |
|
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|
8081 '<code>^</code>' and '<code>$</code>' have no special meaning and represent themselves. |
|
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|
8082 |
|
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changeset
|
8083 |
|
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changeset
|
8084 |
|
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changeset
|
8085 |
|
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changeset
|
8086 |
|
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|
8087 <h4>Captures:</h4><p> |
|
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|
8088 A pattern can contain sub-patterns enclosed in parentheses; |
|
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changeset
|
8089 they describe <em>captures</em>. |
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8090 When a match succeeds, the substrings of the subject string |
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8091 that match captures are stored (<em>captured</em>) for future use. |
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8092 Captures are numbered according to their left parentheses. |
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8093 For instance, in the pattern <code>"(a*(.)%w(%s*))"</code>, |
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8094 the part of the string matching <code>"a*(.)%w(%s*)"</code> is |
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8095 stored as the first capture (and therefore has number 1); |
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8096 the character matching "<code>.</code>" is captured with number 2, |
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8097 and the part matching "<code>%s*</code>" has number 3. |
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8098 |
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8099 |
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8100 <p> |
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8101 As a special case, the empty capture <code>()</code> captures |
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8102 the current string position (a number). |
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8103 For instance, if we apply the pattern <code>"()aa()"</code> on the |
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8104 string <code>"flaaap"</code>, there will be two captures: 3 and 5. |
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8105 |
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8106 |
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8107 |
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8108 |
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8109 |
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8110 |
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8111 |
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8112 <h3>6.4.2 – <a name="6.4.2">Format Strings for Pack and Unpack</a></h3> |
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8113 |
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8114 <p> |
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8115 The first argument to <a href="#pdf-string.pack"><code>string.pack</code></a>, |
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8116 <a href="#pdf-string.packsize"><code>string.packsize</code></a>, and <a href="#pdf-string.unpack"><code>string.unpack</code></a> |
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8117 is a format string, |
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8118 which describes the layout of the structure being created or read. |
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8119 |
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8120 |
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8121 <p> |
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8122 A format string is a sequence of conversion options. |
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8123 The conversion options are as follows: |
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8124 |
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8125 <ul> |
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8126 <li><b><code><</code>: </b>sets little endian</li> |
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8127 <li><b><code>></code>: </b>sets big endian</li> |
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8128 <li><b><code>=</code>: </b>sets native endian</li> |
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8129 <li><b><code>![<em>n</em>]</code>: </b>sets maximum alignment to <code>n</code> |
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8130 (default is native alignment)</li> |
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8131 <li><b><code>b</code>: </b>a signed byte (<code>char</code>)</li> |
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8132 <li><b><code>B</code>: </b>an unsigned byte (<code>char</code>)</li> |
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8133 <li><b><code>h</code>: </b>a signed <code>short</code> (native size)</li> |
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8134 <li><b><code>H</code>: </b>an unsigned <code>short</code> (native size)</li> |
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8135 <li><b><code>l</code>: </b>a signed <code>long</code> (native size)</li> |
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8136 <li><b><code>L</code>: </b>an unsigned <code>long</code> (native size)</li> |
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8137 <li><b><code>j</code>: </b>a <code>lua_Integer</code></li> |
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8138 <li><b><code>J</code>: </b>a <code>lua_Unsigned</code></li> |
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8139 <li><b><code>T</code>: </b>a <code>size_t</code> (native size)</li> |
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8140 <li><b><code>i[<em>n</em>]</code>: </b>a signed <code>int</code> with <code>n</code> bytes |
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8141 (default is native size)</li> |
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8142 <li><b><code>I[<em>n</em>]</code>: </b>an unsigned <code>int</code> with <code>n</code> bytes |
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8143 (default is native size)</li> |
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8144 <li><b><code>f</code>: </b>a <code>float</code> (native size)</li> |
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8145 <li><b><code>d</code>: </b>a <code>double</code> (native size)</li> |
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8146 <li><b><code>n</code>: </b>a <code>lua_Number</code></li> |
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8147 <li><b><code>c<em>n</em></code>: </b>a fixed-sized string with <code>n</code> bytes</li> |
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8148 <li><b><code>z</code>: </b>a zero-terminated string</li> |
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8149 <li><b><code>s[<em>n</em>]</code>: </b>a string preceded by its length |
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8150 coded as an unsigned integer with <code>n</code> bytes |
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8151 (default is a <code>size_t</code>)</li> |
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8152 <li><b><code>x</code>: </b>one byte of padding</li> |
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8153 <li><b><code>X<em>op</em></code>: </b>an empty item that aligns |
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8154 according to option <code>op</code> |
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8155 (which is otherwise ignored)</li> |
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8156 <li><b>'<code> </code>': </b>(empty space) ignored</li> |
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8157 </ul><p> |
|
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8158 (A "<code>[<em>n</em>]</code>" means an optional integral numeral.) |
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8159 Except for padding, spaces, and configurations |
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8160 (options "<code>xX <=>!</code>"), |
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8161 each option corresponds to an argument (in <a href="#pdf-string.pack"><code>string.pack</code></a>) |
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8162 or a result (in <a href="#pdf-string.unpack"><code>string.unpack</code></a>). |
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8163 |
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8164 |
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8165 <p> |
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8166 For options "<code>!<em>n</em></code>", "<code>s<em>n</em></code>", "<code>i<em>n</em></code>", and "<code>I<em>n</em></code>", |
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8167 <code>n</code> can be any integer between 1 and 16. |
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8168 All integral options check overflows; |
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8169 <a href="#pdf-string.pack"><code>string.pack</code></a> checks whether the given value fits in the given size; |
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8170 <a href="#pdf-string.unpack"><code>string.unpack</code></a> checks whether the read value fits in a Lua integer. |
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8171 |
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8172 |
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8173 <p> |
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8174 Any format string starts as if prefixed by "<code>!1=</code>", |
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8175 that is, |
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8176 with maximum alignment of 1 (no alignment) |
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8177 and native endianness. |
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8178 |
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8179 |
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8180 <p> |
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8181 Alignment works as follows: |
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8182 For each option, |
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8183 the format gets extra padding until the data starts |
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8184 at an offset that is a multiple of the minimum between the |
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8185 option size and the maximum alignment; |
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8186 this minimum must be a power of 2. |
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8187 Options "<code>c</code>" and "<code>z</code>" are not aligned; |
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8188 option "<code>s</code>" follows the alignment of its starting integer. |
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8189 |
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8190 |
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8191 <p> |
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8192 All padding is filled with zeros by <a href="#pdf-string.pack"><code>string.pack</code></a> |
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8193 (and ignored by <a href="#pdf-string.unpack"><code>string.unpack</code></a>). |
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8194 |
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8195 |
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8196 |
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8197 |
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8198 |
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|
8199 |
|
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diff
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|
8200 |
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|
8201 <h2>6.5 – <a name="6.5">UTF-8 Support</a></h2> |
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|
8202 |
|
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8203 <p> |
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8204 This library provides basic support for UTF-8 encoding. |
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8205 It provides all its functions inside the table <a name="pdf-utf8"><code>utf8</code></a>. |
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8206 This library does not provide any support for Unicode other |
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8207 than the handling of the encoding. |
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8208 Any operation that needs the meaning of a character, |
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8209 such as character classification, is outside its scope. |
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8210 |
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|
8211 |
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8212 <p> |
|
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8213 Unless stated otherwise, |
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8214 all functions that expect a byte position as a parameter |
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8215 assume that the given position is either the start of a byte sequence |
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8216 or one plus the length of the subject string. |
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8217 As in the string library, |
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8218 negative indices count from the end of the string. |
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8219 |
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8220 |
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8221 <p> |
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8222 <hr><h3><a name="pdf-utf8.char"><code>utf8.char (···)</code></a></h3> |
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8223 Receives zero or more integers, |
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8224 converts each one to its corresponding UTF-8 byte sequence |
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8225 and returns a string with the concatenation of all these sequences. |
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8226 |
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|
8227 |
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8228 |
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|
8229 |
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8230 <p> |
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8231 <hr><h3><a name="pdf-utf8.charpattern"><code>utf8.charpattern</code></a></h3> |
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8232 The pattern (a string, not a function) "<code>[\0-\x7F\xC2-\xF4][\x80-\xBF]*</code>" |
|
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|
8233 (see <a href="#6.4.1">§6.4.1</a>), |
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|
8234 which matches exactly one UTF-8 byte sequence, |
|
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8235 assuming that the subject is a valid UTF-8 string. |
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|
8236 |
|
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|
8237 |
|
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|
8238 |
|
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|
8239 |
|
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8240 <p> |
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|
8241 <hr><h3><a name="pdf-utf8.codes"><code>utf8.codes (s)</code></a></h3> |
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8242 |
|
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|
8243 |
|
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8244 <p> |
|
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|
8245 Returns values so that the construction |
|
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|
8246 |
|
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|
8247 <pre> |
|
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8248 for p, c in utf8.codes(s) do <em>body</em> end |
|
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8249 </pre><p> |
|
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8250 will iterate over all characters in string <code>s</code>, |
|
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8251 with <code>p</code> being the position (in bytes) and <code>c</code> the code point |
|
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8252 of each character. |
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8253 It raises an error if it meets any invalid byte sequence. |
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|
8254 |
|
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|
8255 |
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|
8256 |
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|
8257 |
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8258 <p> |
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|
8259 <hr><h3><a name="pdf-utf8.codepoint"><code>utf8.codepoint (s [, i [, j]])</code></a></h3> |
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8260 Returns the codepoints (as integers) from all characters in <code>s</code> |
|
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8261 that start between byte position <code>i</code> and <code>j</code> (both included). |
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8262 The default for <code>i</code> is 1 and for <code>j</code> is <code>i</code>. |
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8263 It raises an error if it meets any invalid byte sequence. |
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|
8264 |
|
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|
8265 |
|
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|
8266 |
|
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|
8267 |
|
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|
8268 <p> |
|
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|
8269 <hr><h3><a name="pdf-utf8.len"><code>utf8.len (s [, i [, j]])</code></a></h3> |
|
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8270 Returns the number of UTF-8 characters in string <code>s</code> |
|
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|
8271 that start between positions <code>i</code> and <code>j</code> (both inclusive). |
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|
8272 The default for <code>i</code> is 1 and for <code>j</code> is -1. |
|
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8273 If it finds any invalid byte sequence, |
|
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|
8274 returns a false value plus the position of the first invalid byte. |
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|
8275 |
|
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|
8276 |
|
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|
8277 |
|
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|
8278 |
|
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|
8279 <p> |
|
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|
8280 <hr><h3><a name="pdf-utf8.offset"><code>utf8.offset (s, n [, i])</code></a></h3> |
|
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8281 Returns the position (in bytes) where the encoding of the |
|
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|
8282 <code>n</code>-th character of <code>s</code> |
|
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8283 (counting from position <code>i</code>) starts. |
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|
8284 A negative <code>n</code> gets characters before position <code>i</code>. |
|
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8285 The default for <code>i</code> is 1 when <code>n</code> is non-negative |
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8286 and <code>#s + 1</code> otherwise, |
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8287 so that <code>utf8.offset(s, -n)</code> gets the offset of the |
|
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8288 <code>n</code>-th character from the end of the string. |
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8289 If the specified character is neither in the subject |
|
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8290 nor right after its end, |
|
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|
8291 the function returns <b>nil</b>. |
|
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|
8292 |
|
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|
8293 |
|
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8294 <p> |
|
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|
8295 As a special case, |
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8296 when <code>n</code> is 0 the function returns the start of the encoding |
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8297 of the character that contains the <code>i</code>-th byte of <code>s</code>. |
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8298 |
|
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|
8299 |
|
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|
8300 <p> |
|
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|
8301 This function assumes that <code>s</code> is a valid UTF-8 string. |
|
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|
8302 |
|
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|
8303 |
|
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|
8304 |
|
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|
8305 |
|
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|
8306 |
|
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|
8307 |
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8308 |
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|
8309 <h2>6.6 – <a name="6.6">Table Manipulation</a></h2> |
|
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|
8310 |
|
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|
8311 <p> |
|
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|
8312 This library provides generic functions for table manipulation. |
|
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|
8313 It provides all its functions inside the table <a name="pdf-table"><code>table</code></a>. |
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|
8314 |
|
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diff
changeset
|
8315 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8316 <p> |
|
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parents:
diff
changeset
|
8317 Remember that, whenever an operation needs the length of a table, |
|
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add manual.html as copy of Lua 5.3 Reference Manual
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parents:
diff
changeset
|
8318 the table must be a proper sequence |
|
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diff
changeset
|
8319 or have a <code>__len</code> metamethod (see <a href="#3.4.7">§3.4.7</a>). |
|
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|
8320 All functions ignore non-numeric keys |
|
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parents:
diff
changeset
|
8321 in the tables given as arguments. |
|
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parents:
diff
changeset
|
8322 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8323 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8324 <p> |
|
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Franklin Schmidt <fschmidt@gmail.com>
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diff
changeset
|
8325 <hr><h3><a name="pdf-table.concat"><code>table.concat (list [, sep [, i [, j]]])</code></a></h3> |
|
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add manual.html as copy of Lua 5.3 Reference Manual
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parents:
diff
changeset
|
8326 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8327 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8328 <p> |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8329 Given a list where all elements are strings or numbers, |
|
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add manual.html as copy of Lua 5.3 Reference Manual
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parents:
diff
changeset
|
8330 returns the string <code>list[i]..sep..list[i+1] ··· sep..list[j]</code>. |
|
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diff
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|
8331 The default value for <code>sep</code> is the empty string, |
|
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parents:
diff
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|
8332 the default for <code>i</code> is 1, |
|
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add manual.html as copy of Lua 5.3 Reference Manual
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parents:
diff
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|
8333 and the default for <code>j</code> is <code>#list</code>. |
|
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parents:
diff
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|
8334 If <code>i</code> is greater than <code>j</code>, returns the empty string. |
|
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parents:
diff
changeset
|
8335 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8336 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8337 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8338 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
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|
8339 <p> |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
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|
8340 <hr><h3><a name="pdf-table.insert"><code>table.insert (list, [pos,] value)</code></a></h3> |
|
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parents:
diff
changeset
|
8341 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8342 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8343 <p> |
|
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parents:
diff
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|
8344 Inserts element <code>value</code> at position <code>pos</code> in <code>list</code>, |
|
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parents:
diff
changeset
|
8345 shifting up the elements |
|
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parents:
diff
changeset
|
8346 <code>list[pos], list[pos+1], ···, list[#list]</code>. |
|
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diff
changeset
|
8347 The default value for <code>pos</code> is <code>#list+1</code>, |
|
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parents:
diff
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|
8348 so that a call <code>table.insert(t,x)</code> inserts <code>x</code> at the end |
|
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parents:
diff
changeset
|
8349 of list <code>t</code>. |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8350 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8351 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8352 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8353 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8354 <p> |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8355 <hr><h3><a name="pdf-table.move"><code>table.move (a1, f, e, t [,a2])</code></a></h3> |
|
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parents:
diff
changeset
|
8356 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8357 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8358 <p> |
|
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parents:
diff
changeset
|
8359 Moves elements from table <code>a1</code> to table <code>a2</code>. |
|
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parents:
diff
changeset
|
8360 This function performs the equivalent to the following |
|
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parents:
diff
changeset
|
8361 multiple assignment: |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8362 <code>a2[t],··· = a1[f],···,a1[e]</code>. |
|
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parents:
diff
changeset
|
8363 The default for <code>a2</code> is <code>a1</code>. |
|
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parents:
diff
changeset
|
8364 The destination range can overlap with the source range. |
|
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parents:
diff
changeset
|
8365 Index <code>f</code> must be positive. |
|
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parents:
diff
changeset
|
8366 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8367 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8368 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8369 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8370 <p> |
|
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parents:
diff
changeset
|
8371 <hr><h3><a name="pdf-table.pack"><code>table.pack (···)</code></a></h3> |
|
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parents:
diff
changeset
|
8372 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8373 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8374 <p> |
|
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parents:
diff
changeset
|
8375 Returns a new table with all parameters stored into keys 1, 2, etc. |
|
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parents:
diff
changeset
|
8376 and with a field "<code>n</code>" with the total number of parameters. |
|
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parents:
diff
changeset
|
8377 Note that the resulting table may not be a sequence. |
|
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parents:
diff
changeset
|
8378 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8379 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8380 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8381 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8382 <p> |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8383 <hr><h3><a name="pdf-table.remove"><code>table.remove (list [, pos])</code></a></h3> |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8384 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8385 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8386 <p> |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8387 Removes from <code>list</code> the element at position <code>pos</code>, |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8388 returning the value of the removed element. |
|
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parents:
diff
changeset
|
8389 When <code>pos</code> is an integer between 1 and <code>#list</code>, |
|
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parents:
diff
changeset
|
8390 it shifts down the elements |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8391 <code>list[pos+1], list[pos+2], ···, list[#list]</code> |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8392 and erases element <code>list[#list]</code>; |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8393 The index <code>pos</code> can also be 0 when <code>#list</code> is 0, |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8394 or <code>#list + 1</code>; |
|
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add manual.html as copy of Lua 5.3 Reference Manual
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parents:
diff
changeset
|
8395 in those cases, the function erases the element <code>list[pos]</code>. |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8396 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8397 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8398 <p> |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8399 The default value for <code>pos</code> is <code>#list</code>, |
|
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parents:
diff
changeset
|
8400 so that a call <code>table.remove(l)</code> removes the last element |
|
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parents:
diff
changeset
|
8401 of list <code>l</code>. |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8402 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8403 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8404 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8405 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8406 <p> |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8407 <hr><h3><a name="pdf-table.sort"><code>table.sort (list [, comp])</code></a></h3> |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8408 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8409 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8410 <p> |
|
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parents:
diff
changeset
|
8411 Sorts list elements in a given order, <em>in-place</em>, |
|
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parents:
diff
changeset
|
8412 from <code>list[1]</code> to <code>list[#list]</code>. |
|
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parents:
diff
changeset
|
8413 If <code>comp</code> is given, |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8414 then it must be a function that receives two list elements |
|
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parents:
diff
changeset
|
8415 and returns true when the first element must come |
|
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parents:
diff
changeset
|
8416 before the second in the final order |
|
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parents:
diff
changeset
|
8417 (so that <code>not comp(list[i+1],list[i])</code> will be true after the sort). |
|
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parents:
diff
changeset
|
8418 If <code>comp</code> is not given, |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8419 then the standard Lua operator <code><</code> is used instead. |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8420 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8421 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8422 <p> |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8423 The sort algorithm is not stable; |
|
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parents:
diff
changeset
|
8424 that is, elements considered equal by the given order |
|
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parents:
diff
changeset
|
8425 may have their relative positions changed by the sort. |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8426 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8427 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8428 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8429 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8430 <p> |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8431 <hr><h3><a name="pdf-table.unpack"><code>table.unpack (list [, i [, j]])</code></a></h3> |
|
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add manual.html as copy of Lua 5.3 Reference Manual
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|
8432 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8433 |
|
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Franklin Schmidt <fschmidt@gmail.com>
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diff
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|
8434 <p> |
|
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diff
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|
8435 Returns the elements from the given list. |
|
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parents:
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changeset
|
8436 This function is equivalent to |
|
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diff
changeset
|
8437 |
|
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diff
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|
8438 <pre> |
|
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|
8439 return list[i], list[i+1], ···, list[j] |
|
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add manual.html as copy of Lua 5.3 Reference Manual
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|
8440 </pre><p> |
|
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add manual.html as copy of Lua 5.3 Reference Manual
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|
8441 By default, <code>i</code> is 1 and <code>j</code> is <code>#list</code>. |
|
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add manual.html as copy of Lua 5.3 Reference Manual
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|
8442 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8443 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8444 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8445 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8446 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8447 |
|
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add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8448 |
|
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|
8449 <h2>6.7 – <a name="6.7">Mathematical Functions</a></h2> |
|
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add manual.html as copy of Lua 5.3 Reference Manual
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|
8450 |
|
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diff
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|
8451 <p> |
|
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|
8452 This library provides basic mathematical functions. |
|
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parents:
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|
8453 It provides all its functions and constants inside the table <a name="pdf-math"><code>math</code></a>. |
|
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|
8454 Functions with the annotation "<code>integer/float</code>" give |
|
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|
8455 integer results for integer arguments |
|
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parents:
diff
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|
8456 and float results for float (or mixed) arguments. |
|
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parents:
diff
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|
8457 Rounding functions |
|
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|
8458 (<a href="#pdf-math.ceil"><code>math.ceil</code></a>, <a href="#pdf-math.floor"><code>math.floor</code></a>, and <a href="#pdf-math.modf"><code>math.modf</code></a>) |
|
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parents:
diff
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|
8459 return an integer when the result fits in the range of an integer, |
|
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parents:
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|
8460 or a float otherwise. |
|
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parents:
diff
changeset
|
8461 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8462 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
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|
8463 <p> |
|
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Franklin Schmidt <fschmidt@gmail.com>
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|
8464 <hr><h3><a name="pdf-math.abs"><code>math.abs (x)</code></a></h3> |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8465 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8466 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8467 <p> |
|
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add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8468 Returns the absolute value of <code>x</code>. (integer/float) |
|
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add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8469 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8470 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8471 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8472 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8473 <p> |
|
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Franklin Schmidt <fschmidt@gmail.com>
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|
8474 <hr><h3><a name="pdf-math.acos"><code>math.acos (x)</code></a></h3> |
|
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add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8475 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8476 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8477 <p> |
|
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parents:
diff
changeset
|
8478 Returns the arc cosine of <code>x</code> (in radians). |
|
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add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8479 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8480 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8481 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8482 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8483 <p> |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8484 <hr><h3><a name="pdf-math.asin"><code>math.asin (x)</code></a></h3> |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8485 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8486 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8487 <p> |
|
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diff
changeset
|
8488 Returns the arc sine of <code>x</code> (in radians). |
|
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add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8489 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8490 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8491 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8492 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8493 <p> |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8494 <hr><h3><a name="pdf-math.atan"><code>math.atan (y [, x])</code></a></h3> |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8495 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8496 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8497 <p> |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8498 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8499 Returns the arc tangent of <code>y/x</code> (in radians), |
|
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add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8500 but uses the signs of both parameters to find the |
|
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add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8501 quadrant of the result. |
|
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add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8502 (It also handles correctly the case of <code>x</code> being zero.) |
|
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add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8503 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8504 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8505 <p> |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8506 The default value for <code>x</code> is 1, |
|
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add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8507 so that the call <code>math.atan(y)</code> |
|
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add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8508 returns the arc tangent of <code>y</code>. |
|
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add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8509 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8510 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8511 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8512 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8513 <p> |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8514 <hr><h3><a name="pdf-math.ceil"><code>math.ceil (x)</code></a></h3> |
|
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add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8515 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8516 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8517 <p> |
|
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parents:
diff
changeset
|
8518 Returns the smallest integral value larger than or equal to <code>x</code>. |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8519 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8520 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8521 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8522 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8523 <p> |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
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changeset
|
8524 <hr><h3><a name="pdf-math.cos"><code>math.cos (x)</code></a></h3> |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8525 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8526 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8527 <p> |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8528 Returns the cosine of <code>x</code> (assumed to be in radians). |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8529 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8530 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8531 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8532 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8533 <p> |
|
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parents:
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changeset
|
8534 <hr><h3><a name="pdf-math.deg"><code>math.deg (x)</code></a></h3> |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8535 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8536 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8537 <p> |
|
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parents:
diff
changeset
|
8538 Converts the angle <code>x</code> from radians to degrees. |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8539 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8540 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8541 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8542 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8543 <p> |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
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changeset
|
8544 <hr><h3><a name="pdf-math.exp"><code>math.exp (x)</code></a></h3> |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8545 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8546 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
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changeset
|
8547 <p> |
|
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parents:
diff
changeset
|
8548 Returns the value <em>e<sup>x</sup></em> |
|
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parents:
diff
changeset
|
8549 (where <code>e</code> is the base of natural logarithms). |
|
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parents:
diff
changeset
|
8550 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8551 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8552 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8553 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8554 <p> |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8555 <hr><h3><a name="pdf-math.floor"><code>math.floor (x)</code></a></h3> |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8556 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8557 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8558 <p> |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8559 Returns the largest integral value smaller than or equal to <code>x</code>. |
|
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add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8560 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8561 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8562 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8563 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8564 <p> |
|
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add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8565 <hr><h3><a name="pdf-math.fmod"><code>math.fmod (x, y)</code></a></h3> |
|
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add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8566 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8567 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8568 <p> |
|
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add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8569 Returns the remainder of the division of <code>x</code> by <code>y</code> |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8570 that rounds the quotient towards zero. (integer/float) |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8571 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8572 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8573 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8574 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8575 <p> |
|
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add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8576 <hr><h3><a name="pdf-math.huge"><code>math.huge</code></a></h3> |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8577 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8578 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8579 <p> |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8580 The float value <code>HUGE_VAL</code>, |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8581 a value larger than any other numerical value. |
|
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add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8582 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8583 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8584 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8585 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8586 <p> |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8587 <hr><h3><a name="pdf-math.log"><code>math.log (x [, base])</code></a></h3> |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8588 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8589 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8590 <p> |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8591 Returns the logarithm of <code>x</code> in the given base. |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8592 The default for <code>base</code> is <em>e</em> |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8593 (so that the function returns the natural logarithm of <code>x</code>). |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8594 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8595 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8596 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8597 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8598 <p> |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8599 <hr><h3><a name="pdf-math.max"><code>math.max (x, ···)</code></a></h3> |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8600 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8601 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8602 <p> |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8603 Returns the argument with the maximum value, |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8604 according to the Lua operator <code><</code>. (integer/float) |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8605 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8606 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8607 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8608 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8609 <p> |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8610 <hr><h3><a name="pdf-math.maxinteger"><code>math.maxinteger</code></a></h3> |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8611 An integer with the maximum value for an integer. |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8612 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8613 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8614 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8615 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8616 <p> |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8617 <hr><h3><a name="pdf-math.min"><code>math.min (x, ···)</code></a></h3> |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8618 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8619 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8620 <p> |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8621 Returns the argument with the minimum value, |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8622 according to the Lua operator <code><</code>. (integer/float) |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8623 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8624 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8625 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8626 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8627 <p> |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8628 <hr><h3><a name="pdf-math.mininteger"><code>math.mininteger</code></a></h3> |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8629 An integer with the minimum value for an integer. |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8630 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8631 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8632 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8633 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8634 <p> |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8635 <hr><h3><a name="pdf-math.modf"><code>math.modf (x)</code></a></h3> |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8636 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8637 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8638 <p> |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8639 Returns the integral part of <code>x</code> and the fractional part of <code>x</code>. |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8640 Its second result is always a float. |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8641 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8642 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8643 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8644 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8645 <p> |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8646 <hr><h3><a name="pdf-math.pi"><code>math.pi</code></a></h3> |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8647 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8648 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8649 <p> |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8650 The value of <em>π</em>. |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8651 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8652 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8653 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8654 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8655 <p> |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8656 <hr><h3><a name="pdf-math.rad"><code>math.rad (x)</code></a></h3> |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8657 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8658 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8659 <p> |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8660 Converts the angle <code>x</code> from degrees to radians. |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8661 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8662 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8663 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8664 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8665 <p> |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8666 <hr><h3><a name="pdf-math.random"><code>math.random ([m [, n]])</code></a></h3> |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8667 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8668 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8669 <p> |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8670 When called without arguments, |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8671 returns a pseudo-random float with uniform distribution |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8672 in the range <em>[0,1)</em>. |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8673 When called with two integers <code>m</code> and <code>n</code>, |
|
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|
8674 <code>math.random</code> returns a pseudo-random integer |
|
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|
8675 with uniform distribution in the range <em>[m, n]</em>. |
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|
8676 (The value <em>m-n</em> cannot be negative and must fit in a Lua integer.) |
|
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|
8677 The call <code>math.random(n)</code> is equivalent to <code>math.random(1,n)</code>. |
|
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|
8678 |
|
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|
8679 |
|
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|
8680 <p> |
|
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|
8681 This function is an interface to the underling |
|
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|
8682 pseudo-random generator function provided by C. |
|
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|
8683 No guarantees can be given for its statistical properties. |
|
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|
8684 |
|
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|
8685 |
|
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|
8686 |
|
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|
8687 |
|
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|
8688 <p> |
|
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|
8689 <hr><h3><a name="pdf-math.randomseed"><code>math.randomseed (x)</code></a></h3> |
|
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|
8690 |
|
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|
8691 |
|
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|
8692 <p> |
|
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|
8693 Sets <code>x</code> as the "seed" |
|
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|
8694 for the pseudo-random generator: |
|
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|
8695 equal seeds produce equal sequences of numbers. |
|
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|
8696 |
|
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|
8697 |
|
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|
8698 |
|
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|
8699 |
|
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|
8700 <p> |
|
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|
8701 <hr><h3><a name="pdf-math.sin"><code>math.sin (x)</code></a></h3> |
|
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|
8702 |
|
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|
8703 |
|
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|
8704 <p> |
|
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|
8705 Returns the sine of <code>x</code> (assumed to be in radians). |
|
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|
8706 |
|
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|
8707 |
|
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|
8708 |
|
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|
8709 |
|
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|
8710 <p> |
|
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|
8711 <hr><h3><a name="pdf-math.sqrt"><code>math.sqrt (x)</code></a></h3> |
|
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|
8712 |
|
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|
8713 |
|
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|
8714 <p> |
|
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|
8715 Returns the square root of <code>x</code>. |
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|
8716 (You can also use the expression <code>x^0.5</code> to compute this value.) |
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|
8717 |
|
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|
8718 |
|
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|
8719 |
|
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|
8720 |
|
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|
8721 <p> |
|
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|
8722 <hr><h3><a name="pdf-math.tan"><code>math.tan (x)</code></a></h3> |
|
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|
8723 |
|
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|
8724 |
|
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|
8725 <p> |
|
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|
8726 Returns the tangent of <code>x</code> (assumed to be in radians). |
|
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|
8727 |
|
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|
8728 |
|
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|
8729 |
|
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|
8730 |
|
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|
8731 <p> |
|
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|
8732 <hr><h3><a name="pdf-math.tointeger"><code>math.tointeger (x)</code></a></h3> |
|
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|
8733 |
|
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|
8734 |
|
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|
8735 <p> |
|
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|
8736 If the value <code>x</code> is convertible to an integer, |
|
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|
8737 returns that integer. |
|
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|
8738 Otherwise, returns <b>nil</b>. |
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|
8739 |
|
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changeset
|
8740 |
|
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|
8741 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8742 |
|
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|
8743 <p> |
|
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|
8744 <hr><h3><a name="pdf-math.type"><code>math.type (x)</code></a></h3> |
|
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|
8745 |
|
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changeset
|
8746 |
|
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|
8747 <p> |
|
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|
8748 Returns "<code>integer</code>" if <code>x</code> is an integer, |
|
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|
8749 "<code>float</code>" if it is a float, |
|
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|
8750 or <b>nil</b> if <code>x</code> is not a number. |
|
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|
8751 |
|
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|
8752 |
|
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changeset
|
8753 |
|
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changeset
|
8754 |
|
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|
8755 <p> |
|
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|
8756 <hr><h3><a name="pdf-math.ult"><code>math.ult (m, n)</code></a></h3> |
|
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|
8757 |
|
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changeset
|
8758 |
|
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|
8759 <p> |
|
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|
8760 Returns a boolean, |
|
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|
8761 true if integer <code>m</code> is below integer <code>n</code> when |
|
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|
8762 they are compared as unsigned integers. |
|
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changeset
|
8763 |
|
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changeset
|
8764 |
|
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changeset
|
8765 |
|
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changeset
|
8766 |
|
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changeset
|
8767 |
|
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changeset
|
8768 |
|
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changeset
|
8769 |
|
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|
8770 <h2>6.8 – <a name="6.8">Input and Output Facilities</a></h2> |
|
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|
8771 |
|
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changeset
|
8772 <p> |
|
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changeset
|
8773 The I/O library provides two different styles for file manipulation. |
|
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|
8774 The first one uses implicit file handles; |
|
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|
8775 that is, there are operations to set a default input file and a |
|
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changeset
|
8776 default output file, |
|
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|
8777 and all input/output operations are over these default files. |
|
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|
8778 The second style uses explicit file handles. |
|
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|
8779 |
|
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changeset
|
8780 |
|
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changeset
|
8781 <p> |
|
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changeset
|
8782 When using implicit file handles, |
|
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|
8783 all operations are supplied by table <a name="pdf-io"><code>io</code></a>. |
|
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changeset
|
8784 When using explicit file handles, |
|
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|
8785 the operation <a href="#pdf-io.open"><code>io.open</code></a> returns a file handle |
|
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|
8786 and then all operations are supplied as methods of the file handle. |
|
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changeset
|
8787 |
|
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changeset
|
8788 |
|
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changeset
|
8789 <p> |
|
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changeset
|
8790 The table <code>io</code> also provides |
|
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|
8791 three predefined file handles with their usual meanings from C: |
|
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changeset
|
8792 <a name="pdf-io.stdin"><code>io.stdin</code></a>, <a name="pdf-io.stdout"><code>io.stdout</code></a>, and <a name="pdf-io.stderr"><code>io.stderr</code></a>. |
|
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changeset
|
8793 The I/O library never closes these files. |
|
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add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8794 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8795 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8796 <p> |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8797 Unless otherwise stated, |
|
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add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8798 all I/O functions return <b>nil</b> on failure |
|
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add manual.html as copy of Lua 5.3 Reference Manual
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parents:
diff
changeset
|
8799 (plus an error message as a second result and |
|
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add manual.html as copy of Lua 5.3 Reference Manual
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parents:
diff
changeset
|
8800 a system-dependent error code as a third result) |
|
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add manual.html as copy of Lua 5.3 Reference Manual
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parents:
diff
changeset
|
8801 and some value different from <b>nil</b> on success. |
|
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add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8802 On non-POSIX systems, |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8803 the computation of the error message and error code |
|
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add manual.html as copy of Lua 5.3 Reference Manual
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parents:
diff
changeset
|
8804 in case of errors |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8805 may be not thread safe, |
|
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add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8806 because they rely on the global C variable <code>errno</code>. |
|
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add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8807 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8808 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8809 <p> |
|
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add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8810 <hr><h3><a name="pdf-io.close"><code>io.close ([file])</code></a></h3> |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8811 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8812 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8813 <p> |
|
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add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8814 Equivalent to <code>file:close()</code>. |
|
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add manual.html as copy of Lua 5.3 Reference Manual
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parents:
diff
changeset
|
8815 Without a <code>file</code>, closes the default output file. |
|
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parents:
diff
changeset
|
8816 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8817 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8818 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8819 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8820 <p> |
|
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add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8821 <hr><h3><a name="pdf-io.flush"><code>io.flush ()</code></a></h3> |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8822 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8823 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8824 <p> |
|
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add manual.html as copy of Lua 5.3 Reference Manual
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parents:
diff
changeset
|
8825 Equivalent to <code>io.output():flush()</code>. |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
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parents:
diff
changeset
|
8826 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8827 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8828 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8829 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8830 <p> |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8831 <hr><h3><a name="pdf-io.input"><code>io.input ([file])</code></a></h3> |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8832 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8833 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8834 <p> |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8835 When called with a file name, it opens the named file (in text mode), |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8836 and sets its handle as the default input file. |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8837 When called with a file handle, |
|
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parents:
diff
changeset
|
8838 it simply sets this file handle as the default input file. |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8839 When called without parameters, |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8840 it returns the current default input file. |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8841 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8842 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8843 <p> |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8844 In case of errors this function raises the error, |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8845 instead of returning an error code. |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8846 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8847 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8848 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8849 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8850 <p> |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8851 <hr><h3><a name="pdf-io.lines"><code>io.lines ([filename ···])</code></a></h3> |
|
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parents:
diff
changeset
|
8852 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8853 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8854 <p> |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8855 Opens the given file name in read mode |
|
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parents:
diff
changeset
|
8856 and returns an iterator function that |
|
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parents:
diff
changeset
|
8857 works like <code>file:lines(···)</code> over the opened file. |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8858 When the iterator function detects the end of file, |
|
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parents:
diff
changeset
|
8859 it returns no values (to finish the loop) and automatically closes the file. |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8860 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8861 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8862 <p> |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8863 The call <code>io.lines()</code> (with no file name) is equivalent |
|
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add manual.html as copy of Lua 5.3 Reference Manual
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parents:
diff
changeset
|
8864 to <code>io.input():lines("*l")</code>; |
|
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parents:
diff
changeset
|
8865 that is, it iterates over the lines of the default input file. |
|
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parents:
diff
changeset
|
8866 In this case it does not close the file when the loop ends. |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
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parents:
diff
changeset
|
8867 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8868 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8869 <p> |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8870 In case of errors this function raises the error, |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8871 instead of returning an error code. |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8872 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8873 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8874 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8875 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8876 <p> |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8877 <hr><h3><a name="pdf-io.open"><code>io.open (filename [, mode])</code></a></h3> |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8878 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8879 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8880 <p> |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8881 This function opens a file, |
|
e01cddba3433
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parents:
diff
changeset
|
8882 in the mode specified in the string <code>mode</code>. |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8883 It returns a new file handle, |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8884 or, in case of errors, <b>nil</b> plus an error message. |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8885 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8886 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8887 <p> |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8888 The <code>mode</code> string can be any of the following: |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8889 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8890 <ul> |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8891 <li><b>"<code>r</code>": </b> read mode (the default);</li> |
|
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parents:
diff
changeset
|
8892 <li><b>"<code>w</code>": </b> write mode;</li> |
|
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parents:
diff
changeset
|
8893 <li><b>"<code>a</code>": </b> append mode;</li> |
|
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parents:
diff
changeset
|
8894 <li><b>"<code>r+</code>": </b> update mode, all previous data is preserved;</li> |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8895 <li><b>"<code>w+</code>": </b> update mode, all previous data is erased;</li> |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8896 <li><b>"<code>a+</code>": </b> append update mode, previous data is preserved, |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8897 writing is only allowed at the end of file.</li> |
|
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parents:
diff
changeset
|
8898 </ul><p> |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8899 The <code>mode</code> string can also have a '<code>b</code>' at the end, |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8900 which is needed in some systems to open the file in binary mode. |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8901 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8902 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8903 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8904 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8905 <p> |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8906 <hr><h3><a name="pdf-io.output"><code>io.output ([file])</code></a></h3> |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8907 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8908 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8909 <p> |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8910 Similar to <a href="#pdf-io.input"><code>io.input</code></a>, but operates over the default output file. |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8911 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8912 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8913 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8914 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8915 <p> |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8916 <hr><h3><a name="pdf-io.popen"><code>io.popen (prog [, mode])</code></a></h3> |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8917 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8918 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8919 <p> |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8920 This function is system dependent and is not available |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8921 on all platforms. |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8922 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8923 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8924 <p> |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8925 Starts program <code>prog</code> in a separated process and returns |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8926 a file handle that you can use to read data from this program |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8927 (if <code>mode</code> is <code>"r"</code>, the default) |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8928 or to write data to this program |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8929 (if <code>mode</code> is <code>"w"</code>). |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8930 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8931 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8932 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8933 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8934 <p> |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8935 <hr><h3><a name="pdf-io.read"><code>io.read (···)</code></a></h3> |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8936 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8937 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8938 <p> |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8939 Equivalent to <code>io.input():read(···)</code>. |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8940 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8941 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8942 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8943 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8944 <p> |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8945 <hr><h3><a name="pdf-io.tmpfile"><code>io.tmpfile ()</code></a></h3> |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8946 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8947 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8948 <p> |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8949 Returns a handle for a temporary file. |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8950 This file is opened in update mode |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8951 and it is automatically removed when the program ends. |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8952 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8953 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8954 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8955 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8956 <p> |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8957 <hr><h3><a name="pdf-io.type"><code>io.type (obj)</code></a></h3> |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8958 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8959 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8960 <p> |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8961 Checks whether <code>obj</code> is a valid file handle. |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8962 Returns the string <code>"file"</code> if <code>obj</code> is an open file handle, |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8963 <code>"closed file"</code> if <code>obj</code> is a closed file handle, |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8964 or <b>nil</b> if <code>obj</code> is not a file handle. |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8965 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8966 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8967 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8968 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8969 <p> |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8970 <hr><h3><a name="pdf-io.write"><code>io.write (···)</code></a></h3> |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8971 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8972 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8973 <p> |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8974 Equivalent to <code>io.output():write(···)</code>. |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8975 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8976 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8977 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8978 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8979 <p> |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8980 <hr><h3><a name="pdf-file:close"><code>file:close ()</code></a></h3> |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8981 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8982 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8983 <p> |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8984 Closes <code>file</code>. |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8985 Note that files are automatically closed when |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8986 their handles are garbage collected, |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8987 but that takes an unpredictable amount of time to happen. |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8988 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8989 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8990 <p> |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8991 When closing a file handle created with <a href="#pdf-io.popen"><code>io.popen</code></a>, |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8992 <a href="#pdf-file:close"><code>file:close</code></a> returns the same values |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8993 returned by <a href="#pdf-os.execute"><code>os.execute</code></a>. |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8994 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8995 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8996 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8997 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8998 <p> |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
8999 <hr><h3><a name="pdf-file:flush"><code>file:flush ()</code></a></h3> |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
9000 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
9001 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
9002 <p> |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
9003 Saves any written data to <code>file</code>. |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
9004 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
9005 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
9006 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
9007 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
9008 <p> |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
9009 <hr><h3><a name="pdf-file:lines"><code>file:lines (···)</code></a></h3> |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
9010 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
9011 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
9012 <p> |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
9013 Returns an iterator function that, |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
9014 each time it is called, |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
9015 reads the file according to the given formats. |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
9016 When no format is given, |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
9017 uses "<code>l</code>" as a default. |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
9018 As an example, the construction |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
9019 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
9020 <pre> |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
9021 for c in file:lines(1) do <em>body</em> end |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
9022 </pre><p> |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
9023 will iterate over all characters of the file, |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
9024 starting at the current position. |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
9025 Unlike <a href="#pdf-io.lines"><code>io.lines</code></a>, this function does not close the file |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
9026 when the loop ends. |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
9027 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
9028 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
9029 <p> |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
9030 In case of errors this function raises the error, |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
9031 instead of returning an error code. |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
9032 |
|
e01cddba3433
add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
9033 |
|
e01cddba3433
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|
9034 |
|
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diff
changeset
|
9035 |
|
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diff
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|
9036 <p> |
|
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|
9037 <hr><h3><a name="pdf-file:read"><code>file:read (···)</code></a></h3> |
|
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|
9038 |
|
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diff
changeset
|
9039 |
|
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diff
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|
9040 <p> |
|
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|
9041 Reads the file <code>file</code>, |
|
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|
9042 according to the given formats, which specify what to read. |
|
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|
9043 For each format, |
|
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|
9044 the function returns a string or a number with the characters read, |
|
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|
9045 or <b>nil</b> if it cannot read data with the specified format. |
|
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|
9046 (In this latter case, |
|
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|
9047 the function does not read subsequent formats.) |
|
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|
9048 When called without formats, |
|
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|
9049 it uses a default format that reads the next line |
|
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|
9050 (see below). |
|
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|
9051 |
|
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diff
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|
9052 |
|
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|
9053 <p> |
|
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|
9054 The available formats are |
|
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|
9055 |
|
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|
9056 <ul> |
|
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|
9057 |
|
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|
9058 <li><b>"<code>n</code>": </b> |
|
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|
9059 reads a numeral and returns it as a float or an integer, |
|
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|
9060 following the lexical conventions of Lua. |
|
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|
9061 (The numeral may have leading spaces and a sign.) |
|
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|
9062 This format always reads the longest input sequence that |
|
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|
9063 is a valid prefix for a number; |
|
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|
9064 if that prefix does not form a valid number |
|
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|
9065 (e.g., an empty string, "<code>0x</code>", or "<code>3.4e-</code>"), |
|
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|
9066 it is discarded and the function returns <b>nil</b>. |
|
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|
9067 </li> |
|
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|
9068 |
|
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|
9069 <li><b>"<code>i</code>": </b> |
|
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|
9070 reads an integral number and returns it as an integer. |
|
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|
9071 </li> |
|
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|
9072 |
|
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|
9073 <li><b>"<code>a</code>": </b> |
|
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|
9074 reads the whole file, starting at the current position. |
|
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|
9075 On end of file, it returns the empty string. |
|
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|
9076 </li> |
|
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|
9077 |
|
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|
9078 <li><b>"<code>l</code>": </b> |
|
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|
9079 reads the next line skipping the end of line, |
|
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|
9080 returning <b>nil</b> on end of file. |
|
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|
9081 This is the default format. |
|
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|
9082 </li> |
|
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|
9083 |
|
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|
9084 <li><b>"<code>L</code>": </b> |
|
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|
9085 reads the next line keeping the end-of-line character (if present), |
|
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diff
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|
9086 returning <b>nil</b> on end of file. |
|
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|
9087 </li> |
|
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|
9088 |
|
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|
9089 <li><b><em>number</em>: </b> |
|
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|
9090 reads a string with up to this number of bytes, |
|
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|
9091 returning <b>nil</b> on end of file. |
|
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|
9092 If <code>number</code> is zero, |
|
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|
9093 it reads nothing and returns an empty string, |
|
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|
9094 or <b>nil</b> on end of file. |
|
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|
9095 </li> |
|
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diff
changeset
|
9096 |
|
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|
9097 </ul><p> |
|
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|
9098 The formats "<code>l</code>" and "<code>L</code>" should be used only for text files. |
|
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changeset
|
9099 |
|
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diff
changeset
|
9100 |
|
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Franklin Schmidt <fschmidt@gmail.com>
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diff
changeset
|
9101 |
|
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Franklin Schmidt <fschmidt@gmail.com>
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diff
changeset
|
9102 |
|
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changeset
|
9103 <p> |
|
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|
9104 <hr><h3><a name="pdf-file:seek"><code>file:seek ([whence [, offset]])</code></a></h3> |
|
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|
9105 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
9106 |
|
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|
9107 <p> |
|
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|
9108 Sets and gets the file position, |
|
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|
9109 measured from the beginning of the file, |
|
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changeset
|
9110 to the position given by <code>offset</code> plus a base |
|
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|
9111 specified by the string <code>whence</code>, as follows: |
|
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|
9112 |
|
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changeset
|
9113 <ul> |
|
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|
9114 <li><b>"<code>set</code>": </b> base is position 0 (beginning of the file);</li> |
|
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|
9115 <li><b>"<code>cur</code>": </b> base is current position;</li> |
|
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|
9116 <li><b>"<code>end</code>": </b> base is end of file;</li> |
|
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|
9117 </ul><p> |
|
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|
9118 In case of success, <code>seek</code> returns the final file position, |
|
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|
9119 measured in bytes from the beginning of the file. |
|
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|
9120 If <code>seek</code> fails, it returns <b>nil</b>, |
|
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|
9121 plus a string describing the error. |
|
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changeset
|
9122 |
|
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changeset
|
9123 |
|
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changeset
|
9124 <p> |
|
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changeset
|
9125 The default value for <code>whence</code> is <code>"cur"</code>, |
|
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|
9126 and for <code>offset</code> is 0. |
|
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|
9127 Therefore, the call <code>file:seek()</code> returns the current |
|
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changeset
|
9128 file position, without changing it; |
|
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changeset
|
9129 the call <code>file:seek("set")</code> sets the position to the |
|
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changeset
|
9130 beginning of the file (and returns 0); |
|
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|
9131 and the call <code>file:seek("end")</code> sets the position to the |
|
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|
9132 end of the file, and returns its size. |
|
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|
9133 |
|
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changeset
|
9134 |
|
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changeset
|
9135 |
|
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changeset
|
9136 |
|
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|
9137 <p> |
|
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|
9138 <hr><h3><a name="pdf-file:setvbuf"><code>file:setvbuf (mode [, size])</code></a></h3> |
|
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|
9139 |
|
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changeset
|
9140 |
|
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changeset
|
9141 <p> |
|
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changeset
|
9142 Sets the buffering mode for an output file. |
|
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|
9143 There are three available modes: |
|
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changeset
|
9144 |
|
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changeset
|
9145 <ul> |
|
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changeset
|
9146 |
|
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|
9147 <li><b>"<code>no</code>": </b> |
|
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changeset
|
9148 no buffering; the result of any output operation appears immediately. |
|
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changeset
|
9149 </li> |
|
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changeset
|
9150 |
|
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changeset
|
9151 <li><b>"<code>full</code>": </b> |
|
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9152 full buffering; output operation is performed only |
|
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|
9153 when the buffer is full or when |
|
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|
9154 you explicitly <code>flush</code> the file (see <a href="#pdf-io.flush"><code>io.flush</code></a>). |
|
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9155 </li> |
|
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|
9156 |
|
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9157 <li><b>"<code>line</code>": </b> |
|
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9158 line buffering; output is buffered until a newline is output |
|
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9159 or there is any input from some special files |
|
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9160 (such as a terminal device). |
|
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9161 </li> |
|
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|
9162 |
|
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9163 </ul><p> |
|
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9164 For the last two cases, <code>size</code> |
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9165 specifies the size of the buffer, in bytes. |
|
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9166 The default is an appropriate size. |
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|
9167 |
|
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|
9168 |
|
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|
9169 |
|
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|
9170 |
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9171 <p> |
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|
9172 <hr><h3><a name="pdf-file:write"><code>file:write (···)</code></a></h3> |
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9173 |
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|
9174 |
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9175 <p> |
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|
9176 Writes the value of each of its arguments to <code>file</code>. |
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9177 The arguments must be strings or numbers. |
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9178 |
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|
9179 |
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9180 <p> |
|
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9181 In case of success, this function returns <code>file</code>. |
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9182 Otherwise it returns <b>nil</b> plus a string describing the error. |
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9183 |
|
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|
9184 |
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|
9185 |
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|
9186 |
|
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|
9187 |
|
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|
9188 |
|
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|
9189 |
|
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|
9190 <h2>6.9 – <a name="6.9">Operating System Facilities</a></h2> |
|
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|
9191 |
|
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|
9192 <p> |
|
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|
9193 This library is implemented through table <a name="pdf-os"><code>os</code></a>. |
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|
9194 |
|
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|
9195 |
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9196 <p> |
|
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9197 <hr><h3><a name="pdf-os.clock"><code>os.clock ()</code></a></h3> |
|
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|
9198 |
|
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|
9199 |
|
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|
9200 <p> |
|
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|
9201 Returns an approximation of the amount in seconds of CPU time |
|
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|
9202 used by the program. |
|
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|
9203 |
|
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|
9204 |
|
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|
9205 |
|
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|
9206 |
|
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9207 <p> |
|
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9208 <hr><h3><a name="pdf-os.date"><code>os.date ([format [, time]])</code></a></h3> |
|
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|
9209 |
|
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|
9210 |
|
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|
9211 <p> |
|
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|
9212 Returns a string or a table containing date and time, |
|
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|
9213 formatted according to the given string <code>format</code>. |
|
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|
9214 |
|
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|
9215 |
|
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|
9216 <p> |
|
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|
9217 If the <code>time</code> argument is present, |
|
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|
9218 this is the time to be formatted |
|
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|
9219 (see the <a href="#pdf-os.time"><code>os.time</code></a> function for a description of this value). |
|
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|
9220 Otherwise, <code>date</code> formats the current time. |
|
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|
9221 |
|
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|
9222 |
|
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|
9223 <p> |
|
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|
9224 If <code>format</code> starts with '<code>!</code>', |
|
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|
9225 then the date is formatted in Coordinated Universal Time. |
|
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|
9226 After this optional character, |
|
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|
9227 if <code>format</code> is the string "<code>*t</code>", |
|
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|
9228 then <code>date</code> returns a table with the following fields: |
|
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|
9229 <code>year</code> (four digits), <code>month</code> (1–12), <code>day</code> (1–31), |
|
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|
9230 <code>hour</code> (0–23), <code>min</code> (0–59), <code>sec</code> (0–61), |
|
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9231 <code>wday</code> (weekday, Sunday is 1), |
|
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|
9232 <code>yday</code> (day of the year), |
|
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|
9233 and <code>isdst</code> (daylight saving flag, a boolean). |
|
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|
9234 This last field may be absent |
|
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|
9235 if the information is not available. |
|
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|
9236 |
|
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|
9237 |
|
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|
9238 <p> |
|
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|
9239 If <code>format</code> is not "<code>*t</code>", |
|
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|
9240 then <code>date</code> returns the date as a string, |
|
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|
9241 formatted according to the same rules as the ISO C function <code>strftime</code>. |
|
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|
9242 |
|
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|
9243 |
|
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|
9244 <p> |
|
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|
9245 When called without arguments, |
|
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|
9246 <code>date</code> returns a reasonable date and time representation that depends on |
|
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9247 the host system and on the current locale |
|
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|
9248 (that is, <code>os.date()</code> is equivalent to <code>os.date("%c")</code>). |
|
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|
9249 |
|
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|
9250 |
|
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|
9251 <p> |
|
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|
9252 On non-POSIX systems, |
|
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9253 this function may be not thread safe |
|
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|
9254 because of its reliance on C function <code>gmtime</code> and C function <code>localtime</code>. |
|
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|
9255 |
|
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|
9256 |
|
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|
9257 |
|
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|
9258 |
|
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|
9259 <p> |
|
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|
9260 <hr><h3><a name="pdf-os.difftime"><code>os.difftime (t2, t1)</code></a></h3> |
|
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|
9261 |
|
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changeset
|
9262 |
|
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|
9263 <p> |
|
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|
9264 Returns the difference, in seconds, |
|
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|
9265 from time <code>t1</code> to time <code>t2</code> |
|
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|
9266 (where the times are values returned by <a href="#pdf-os.time"><code>os.time</code></a>). |
|
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|
9267 In POSIX, Windows, and some other systems, |
|
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|
9268 this value is exactly <code>t2</code><em>-</em><code>t1</code>. |
|
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|
9269 |
|
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add manual.html as copy of Lua 5.3 Reference Manual
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
9270 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
9271 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
9272 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
9273 <p> |
|
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add manual.html as copy of Lua 5.3 Reference Manual
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parents:
diff
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|
9274 <hr><h3><a name="pdf-os.execute"><code>os.execute ([command])</code></a></h3> |
|
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diff
changeset
|
9275 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
9276 |
|
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Franklin Schmidt <fschmidt@gmail.com>
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diff
changeset
|
9277 <p> |
|
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diff
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|
9278 This function is equivalent to the ISO C function <code>system</code>. |
|
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|
9279 It passes <code>command</code> to be executed by an operating system shell. |
|
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|
9280 Its first result is <b>true</b> |
|
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|
9281 if the command terminated successfully, |
|
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diff
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|
9282 or <b>nil</b> otherwise. |
|
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parents:
diff
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|
9283 After this first result |
|
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|
9284 the function returns a string plus a number, |
|
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diff
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|
9285 as follows: |
|
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parents:
diff
changeset
|
9286 |
|
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parents:
diff
changeset
|
9287 <ul> |
|
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diff
changeset
|
9288 |
|
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|
9289 <li><b>"<code>exit</code>": </b> |
|
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|
9290 the command terminated normally; |
|
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diff
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|
9291 the following number is the exit status of the command. |
|
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|
9292 </li> |
|
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diff
changeset
|
9293 |
|
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diff
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|
9294 <li><b>"<code>signal</code>": </b> |
|
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|
9295 the command was terminated by a signal; |
|
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diff
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|
9296 the following number is the signal that terminated the command. |
|
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|
9297 </li> |
|
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diff
changeset
|
9298 |
|
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parents:
diff
changeset
|
9299 </ul> |
|
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parents:
diff
changeset
|
9300 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
9301 <p> |
|
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parents:
diff
changeset
|
9302 When called without a <code>command</code>, |
|
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parents:
diff
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|
9303 <code>os.execute</code> returns a boolean that is true if a shell is available. |
|
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changeset
|
9304 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
9305 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
9306 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
9307 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
9308 <p> |
|
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diff
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|
9309 <hr><h3><a name="pdf-os.exit"><code>os.exit ([code [, close]])</code></a></h3> |
|
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parents:
diff
changeset
|
9310 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
9311 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
9312 <p> |
|
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parents:
diff
changeset
|
9313 Calls the ISO C function <code>exit</code> to terminate the host program. |
|
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diff
changeset
|
9314 If <code>code</code> is <b>true</b>, |
|
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parents:
diff
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|
9315 the returned status is <code>EXIT_SUCCESS</code>; |
|
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parents:
diff
changeset
|
9316 if <code>code</code> is <b>false</b>, |
|
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parents:
diff
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|
9317 the returned status is <code>EXIT_FAILURE</code>; |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
9318 if <code>code</code> is a number, |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
9319 the returned status is this number. |
|
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diff
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|
9320 The default value for <code>code</code> is <b>true</b>. |
|
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parents:
diff
changeset
|
9321 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
9322 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
9323 <p> |
|
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parents:
diff
changeset
|
9324 If the optional second argument <code>close</code> is true, |
|
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parents:
diff
changeset
|
9325 closes the Lua state before exiting. |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
9326 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
9327 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
9328 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
9329 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
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|
9330 <p> |
|
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Franklin Schmidt <fschmidt@gmail.com>
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diff
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|
9331 <hr><h3><a name="pdf-os.getenv"><code>os.getenv (varname)</code></a></h3> |
|
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diff
changeset
|
9332 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
9333 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
9334 <p> |
|
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parents:
diff
changeset
|
9335 Returns the value of the process environment variable <code>varname</code>, |
|
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parents:
diff
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|
9336 or <b>nil</b> if the variable is not defined. |
|
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parents:
diff
changeset
|
9337 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
9338 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
9339 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
9340 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
9341 <p> |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
9342 <hr><h3><a name="pdf-os.remove"><code>os.remove (filename)</code></a></h3> |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
9343 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
9344 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
9345 <p> |
|
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parents:
diff
changeset
|
9346 Deletes the file (or empty directory, on POSIX systems) |
|
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diff
changeset
|
9347 with the given name. |
|
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parents:
diff
changeset
|
9348 If this function fails, it returns <b>nil</b>, |
|
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parents:
diff
changeset
|
9349 plus a string describing the error and the error code. |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
9350 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
9351 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
9352 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
9353 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
9354 <p> |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
9355 <hr><h3><a name="pdf-os.rename"><code>os.rename (oldname, newname)</code></a></h3> |
|
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parents:
diff
changeset
|
9356 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
9357 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
9358 <p> |
|
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parents:
diff
changeset
|
9359 Renames file or directory named <code>oldname</code> to <code>newname</code>. |
|
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parents:
diff
changeset
|
9360 If this function fails, it returns <b>nil</b>, |
|
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diff
changeset
|
9361 plus a string describing the error and the error code. |
|
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parents:
diff
changeset
|
9362 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
9363 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
9364 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
9365 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
9366 <p> |
|
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changeset
|
9367 <hr><h3><a name="pdf-os.setlocale"><code>os.setlocale (locale [, category])</code></a></h3> |
|
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changeset
|
9368 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
9369 |
|
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parents:
diff
changeset
|
9370 <p> |
|
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diff
changeset
|
9371 Sets the current locale of the program. |
|
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diff
changeset
|
9372 <code>locale</code> is a system-dependent string specifying a locale; |
|
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diff
changeset
|
9373 <code>category</code> is an optional string describing which category to change: |
|
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diff
changeset
|
9374 <code>"all"</code>, <code>"collate"</code>, <code>"ctype"</code>, |
|
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changeset
|
9375 <code>"monetary"</code>, <code>"numeric"</code>, or <code>"time"</code>; |
|
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diff
changeset
|
9376 the default category is <code>"all"</code>. |
|
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parents:
diff
changeset
|
9377 The function returns the name of the new locale, |
|
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diff
changeset
|
9378 or <b>nil</b> if the request cannot be honored. |
|
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parents:
diff
changeset
|
9379 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
9380 |
|
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parents:
diff
changeset
|
9381 <p> |
|
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parents:
diff
changeset
|
9382 If <code>locale</code> is the empty string, |
|
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parents:
diff
changeset
|
9383 the current locale is set to an implementation-defined native locale. |
|
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diff
changeset
|
9384 If <code>locale</code> is the string "<code>C</code>", |
|
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parents:
diff
changeset
|
9385 the current locale is set to the standard C locale. |
|
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parents:
diff
changeset
|
9386 |
|
e01cddba3433
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
9387 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
9388 <p> |
|
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changeset
|
9389 When called with <b>nil</b> as the first argument, |
|
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|
9390 this function only returns the name of the current locale |
|
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|
9391 for the given category. |
|
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|
9392 |
|
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diff
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|
9393 |
|
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diff
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|
9394 <p> |
|
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|
9395 This function may be not thread safe |
|
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|
9396 because of its reliance on C function <code>setlocale</code>. |
|
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|
9397 |
|
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diff
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|
9398 |
|
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diff
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|
9399 |
|
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|
9400 |
|
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|
9401 <p> |
|
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|
9402 <hr><h3><a name="pdf-os.time"><code>os.time ([table])</code></a></h3> |
|
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|
9403 |
|
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diff
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|
9404 |
|
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diff
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|
9405 <p> |
|
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|
9406 Returns the current time when called without arguments, |
|
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|
9407 or a time representing the date and time specified by the given table. |
|
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|
9408 This table must have fields <code>year</code>, <code>month</code>, and <code>day</code>, |
|
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|
9409 and may have fields |
|
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|
9410 <code>hour</code> (default is 12), |
|
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parents:
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|
9411 <code>min</code> (default is 0), |
|
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|
9412 <code>sec</code> (default is 0), |
|
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diff
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|
9413 and <code>isdst</code> (default is <b>nil</b>). |
|
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|
9414 For a description of these fields, see the <a href="#pdf-os.date"><code>os.date</code></a> function. |
|
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|
9415 |
|
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diff
changeset
|
9416 |
|
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diff
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|
9417 <p> |
|
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diff
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|
9418 The returned value is a number, whose meaning depends on your system. |
|
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|
9419 In POSIX, Windows, and some other systems, |
|
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|
9420 this number counts the number |
|
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parents:
diff
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|
9421 of seconds since some given start time (the "epoch"). |
|
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diff
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|
9422 In other systems, the meaning is not specified, |
|
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diff
changeset
|
9423 and the number returned by <code>time</code> can be used only as an argument to |
|
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|
9424 <a href="#pdf-os.date"><code>os.date</code></a> and <a href="#pdf-os.difftime"><code>os.difftime</code></a>. |
|
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diff
changeset
|
9425 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
9426 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
9427 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
9428 |
|
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Franklin Schmidt <fschmidt@gmail.com>
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diff
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|
9429 <p> |
|
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|
9430 <hr><h3><a name="pdf-os.tmpname"><code>os.tmpname ()</code></a></h3> |
|
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diff
changeset
|
9431 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
9432 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
9433 <p> |
|
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diff
changeset
|
9434 Returns a string with a file name that can |
|
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|
9435 be used for a temporary file. |
|
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changeset
|
9436 The file must be explicitly opened before its use |
|
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parents:
diff
changeset
|
9437 and explicitly removed when no longer needed. |
|
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diff
changeset
|
9438 |
|
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Franklin Schmidt <fschmidt@gmail.com>
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diff
changeset
|
9439 |
|
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Franklin Schmidt <fschmidt@gmail.com>
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diff
changeset
|
9440 <p> |
|
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diff
changeset
|
9441 On POSIX systems, |
|
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parents:
diff
changeset
|
9442 this function also creates a file with that name, |
|
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diff
changeset
|
9443 to avoid security risks. |
|
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diff
changeset
|
9444 (Someone else might create the file with wrong permissions |
|
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parents:
diff
changeset
|
9445 in the time between getting the name and creating the file.) |
|
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parents:
diff
changeset
|
9446 You still have to open the file to use it |
|
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add manual.html as copy of Lua 5.3 Reference Manual
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parents:
diff
changeset
|
9447 and to remove it (even if you do not use it). |
|
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changeset
|
9448 |
|
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Franklin Schmidt <fschmidt@gmail.com>
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diff
changeset
|
9449 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
9450 <p> |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
9451 When possible, |
|
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Franklin Schmidt <fschmidt@gmail.com>
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diff
changeset
|
9452 you may prefer to use <a href="#pdf-io.tmpfile"><code>io.tmpfile</code></a>, |
|
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Franklin Schmidt <fschmidt@gmail.com>
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diff
changeset
|
9453 which automatically removes the file when the program ends. |
|
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diff
changeset
|
9454 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
9455 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
9456 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
9457 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
9458 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
9459 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
9460 |
|
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diff
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|
9461 <h2>6.10 – <a name="6.10">The Debug Library</a></h2> |
|
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changeset
|
9462 |
|
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diff
changeset
|
9463 <p> |
|
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diff
changeset
|
9464 This library provides |
|
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diff
changeset
|
9465 the functionality of the debug interface (<a href="#4.9">§4.9</a>) to Lua programs. |
|
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changeset
|
9466 You should exert care when using this library. |
|
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changeset
|
9467 Several of its functions |
|
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changeset
|
9468 violate basic assumptions about Lua code |
|
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diff
changeset
|
9469 (e.g., that variables local to a function |
|
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parents:
diff
changeset
|
9470 cannot be accessed from outside; |
|
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diff
changeset
|
9471 that userdata metatables cannot be changed by Lua code; |
|
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changeset
|
9472 that Lua programs do not crash) |
|
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diff
changeset
|
9473 and therefore can compromise otherwise secure code. |
|
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diff
changeset
|
9474 Moreover, some functions in this library may be slow. |
|
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diff
changeset
|
9475 |
|
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diff
changeset
|
9476 |
|
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diff
changeset
|
9477 <p> |
|
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diff
changeset
|
9478 All functions in this library are provided |
|
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changeset
|
9479 inside the <a name="pdf-debug"><code>debug</code></a> table. |
|
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changeset
|
9480 All functions that operate over a thread |
|
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changeset
|
9481 have an optional first argument which is the |
|
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changeset
|
9482 thread to operate over. |
|
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diff
changeset
|
9483 The default is always the current thread. |
|
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changeset
|
9484 |
|
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diff
changeset
|
9485 |
|
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|
9486 <p> |
|
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|
9487 <hr><h3><a name="pdf-debug.debug"><code>debug.debug ()</code></a></h3> |
|
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changeset
|
9488 |
|
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diff
changeset
|
9489 |
|
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changeset
|
9490 <p> |
|
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changeset
|
9491 Enters an interactive mode with the user, |
|
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changeset
|
9492 running each string that the user enters. |
|
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|
9493 Using simple commands and other debug facilities, |
|
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changeset
|
9494 the user can inspect global and local variables, |
|
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|
9495 change their values, evaluate expressions, and so on. |
|
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diff
changeset
|
9496 A line containing only the word <code>cont</code> finishes this function, |
|
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changeset
|
9497 so that the caller continues its execution. |
|
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changeset
|
9498 |
|
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diff
changeset
|
9499 |
|
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changeset
|
9500 <p> |
|
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changeset
|
9501 Note that commands for <code>debug.debug</code> are not lexically nested |
|
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changeset
|
9502 within any function and so have no direct access to local variables. |
|
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changeset
|
9503 |
|
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changeset
|
9504 |
|
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parents:
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changeset
|
9505 |
|
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changeset
|
9506 |
|
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changeset
|
9507 <p> |
|
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diff
changeset
|
9508 <hr><h3><a name="pdf-debug.gethook"><code>debug.gethook ([thread])</code></a></h3> |
|
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|
9509 |
|
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|
9510 |
|
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|
9511 <p> |
|
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|
9512 Returns the current hook settings of the thread, as three values: |
|
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|
9513 the current hook function, the current hook mask, |
|
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|
9514 and the current hook count |
|
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|
9515 (as set by the <a href="#pdf-debug.sethook"><code>debug.sethook</code></a> function). |
|
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|
9516 |
|
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|
9517 |
|
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|
9518 |
|
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|
9519 |
|
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|
9520 <p> |
|
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|
9521 <hr><h3><a name="pdf-debug.getinfo"><code>debug.getinfo ([thread,] f [, what])</code></a></h3> |
|
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|
9522 |
|
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|
9523 |
|
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|
9524 <p> |
|
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|
9525 Returns a table with information about a function. |
|
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|
9526 You can give the function directly |
|
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|
9527 or you can give a number as the value of <code>f</code>, |
|
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|
9528 which means the function running at level <code>f</code> of the call stack |
|
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|
9529 of the given thread: |
|
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|
9530 level 0 is the current function (<code>getinfo</code> itself); |
|
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|
9531 level 1 is the function that called <code>getinfo</code> |
|
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|
9532 (except for tail calls, which do not count on the stack); |
|
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|
9533 and so on. |
|
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|
9534 If <code>f</code> is a number larger than the number of active functions, |
|
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|
9535 then <code>getinfo</code> returns <b>nil</b>. |
|
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|
9536 |
|
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|
9537 |
|
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|
9538 <p> |
|
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|
9539 The returned table can contain all the fields returned by <a href="#lua_getinfo"><code>lua_getinfo</code></a>, |
|
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|
9540 with the string <code>what</code> describing which fields to fill in. |
|
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|
9541 The default for <code>what</code> is to get all information available, |
|
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|
9542 except the table of valid lines. |
|
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|
9543 If present, |
|
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|
9544 the option '<code>f</code>' |
|
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|
9545 adds a field named <code>func</code> with the function itself. |
|
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|
9546 If present, |
|
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|
9547 the option '<code>L</code>' |
|
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|
9548 adds a field named <code>activelines</code> with the table of |
|
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|
9549 valid lines. |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
9550 |
|
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Franklin Schmidt <fschmidt@gmail.com>
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diff
changeset
|
9551 |
|
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|
9552 <p> |
|
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|
9553 For instance, the expression <code>debug.getinfo(1,"n").name</code> returns |
|
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|
9554 a table with a name for the current function, |
|
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parents:
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|
9555 if a reasonable name can be found, |
|
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diff
changeset
|
9556 and the expression <code>debug.getinfo(print)</code> |
|
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|
9557 returns a table with all available information |
|
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diff
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|
9558 about the <a href="#pdf-print"><code>print</code></a> function. |
|
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diff
changeset
|
9559 |
|
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Franklin Schmidt <fschmidt@gmail.com>
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diff
changeset
|
9560 |
|
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Franklin Schmidt <fschmidt@gmail.com>
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diff
changeset
|
9561 |
|
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Franklin Schmidt <fschmidt@gmail.com>
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diff
changeset
|
9562 |
|
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|
9563 <p> |
|
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|
9564 <hr><h3><a name="pdf-debug.getlocal"><code>debug.getlocal ([thread,] f, local)</code></a></h3> |
|
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|
9565 |
|
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Franklin Schmidt <fschmidt@gmail.com>
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diff
changeset
|
9566 |
|
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|
9567 <p> |
|
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|
9568 This function returns the name and the value of the local variable |
|
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|
9569 with index <code>local</code> of the function at level <code>f</code> of the stack. |
|
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|
9570 This function accesses not only explicit local variables, |
|
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|
9571 but also parameters, temporaries, etc. |
|
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changeset
|
9572 |
|
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Franklin Schmidt <fschmidt@gmail.com>
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diff
changeset
|
9573 |
|
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|
9574 <p> |
|
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|
9575 The first parameter or local variable has index 1, and so on, |
|
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|
9576 following the order that they are declared in the code, |
|
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|
9577 counting only the variables that are active |
|
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|
9578 in the current scope of the function. |
|
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changeset
|
9579 Negative indices refer to vararg parameters; |
|
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|
9580 -1 is the first vararg parameter. |
|
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changeset
|
9581 The function returns <b>nil</b> if there is no variable with the given index, |
|
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changeset
|
9582 and raises an error when called with a level out of range. |
|
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|
9583 (You can call <a href="#pdf-debug.getinfo"><code>debug.getinfo</code></a> to check whether the level is valid.) |
|
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changeset
|
9584 |
|
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Franklin Schmidt <fschmidt@gmail.com>
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diff
changeset
|
9585 |
|
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changeset
|
9586 <p> |
|
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changeset
|
9587 Variable names starting with '<code>(</code>' (open parenthesis) |
|
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|
9588 represent variables with no known names |
|
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changeset
|
9589 (internal variables such as loop control variables, |
|
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diff
changeset
|
9590 and variables from chunks saved without debug information). |
|
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changeset
|
9591 |
|
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changeset
|
9592 |
|
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Franklin Schmidt <fschmidt@gmail.com>
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changeset
|
9593 <p> |
|
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changeset
|
9594 The parameter <code>f</code> may also be a function. |
|
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changeset
|
9595 In that case, <code>getlocal</code> returns only the name of function parameters. |
|
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changeset
|
9596 |
|
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changeset
|
9597 |
|
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Franklin Schmidt <fschmidt@gmail.com>
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changeset
|
9598 |
|
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Franklin Schmidt <fschmidt@gmail.com>
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changeset
|
9599 |
|
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changeset
|
9600 <p> |
|
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|
9601 <hr><h3><a name="pdf-debug.getmetatable"><code>debug.getmetatable (value)</code></a></h3> |
|
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changeset
|
9602 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
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changeset
|
9603 |
|
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changeset
|
9604 <p> |
|
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changeset
|
9605 Returns the metatable of the given <code>value</code> |
|
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|
9606 or <b>nil</b> if it does not have a metatable. |
|
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changeset
|
9607 |
|
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changeset
|
9608 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
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changeset
|
9609 |
|
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Franklin Schmidt <fschmidt@gmail.com>
parents:
diff
changeset
|
9610 |
|
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changeset
|
9611 <p> |
|
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changeset
|
9612 <hr><h3><a name="pdf-debug.getregistry"><code>debug.getregistry ()</code></a></h3> |
|
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changeset
|
9613 |
|
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changeset
|
9614 |
|
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changeset
|
9615 <p> |
|
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changeset
|
9616 Returns the registry table (see <a href="#4.5">§4.5</a>). |
|
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changeset
|
9617 |
|
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diff
changeset
|
9618 |
|
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changeset
|
9619 |
|
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changeset
|
9620 |
|
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changeset
|
9621 <p> |
|
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changeset
|
9622 <hr><h3><a name="pdf-debug.getupvalue"><code>debug.getupvalue (f, up)</code></a></h3> |
|
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changeset
|
9623 |
|
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Franklin Schmidt <fschmidt@gmail.com>
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changeset
|
9624 |
|
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changeset
|
9625 <p> |
|
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changeset
|
9626 This function returns the name and the value of the upvalue |
|
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|
9627 with index <code>up</code> of the function <code>f</code>. |
|
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|
9628 The function returns <b>nil</b> if there is no upvalue with the given index. |
|
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|
9629 |
|
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|
9630 |
|
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|
9631 <p> |
|
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|
9632 Variable names starting with '<code>(</code>' (open parenthesis) |
|
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|
9633 represent variables with no known names |
|
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|
9634 (variables from chunks saved without debug information). |
|
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|
9635 |
|
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|
9636 |
|
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|
9637 |
|
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|
9638 |
|
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|
9639 <p> |
|
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|
9640 <hr><h3><a name="pdf-debug.getuservalue"><code>debug.getuservalue (u)</code></a></h3> |
|
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|
9641 |
|
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|
9642 |
|
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|
9643 <p> |
|
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|
9644 Returns the Lua value associated to <code>u</code>. |
|
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|
9645 If <code>u</code> is not a userdata, |
|
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|
9646 returns <b>nil</b>. |
|
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|
9647 |
|
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|
9648 |
|
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Franklin Schmidt <fschmidt@gmail.com>
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diff
changeset
|
9649 |
|
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Franklin Schmidt <fschmidt@gmail.com>
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diff
changeset
|
9650 |
|
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|
9651 <p> |
|
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|
9652 <hr><h3><a name="pdf-debug.sethook"><code>debug.sethook ([thread,] hook, mask [, count])</code></a></h3> |
|
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|
9653 |
|
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diff
changeset
|
9654 |
|
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|
9655 <p> |
|
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|
9656 Sets the given function as a hook. |
|
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|
9657 The string <code>mask</code> and the number <code>count</code> describe |
|
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|
9658 when the hook will be called. |
|
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|
9659 The string mask may have any combination of the following characters, |
|
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|
9660 with the given meaning: |
|
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diff
changeset
|
9661 |
|
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diff
changeset
|
9662 <ul> |
|
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|
9663 <li><b>'<code>c</code>': </b> the hook is called every time Lua calls a function;</li> |
|
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|
9664 <li><b>'<code>r</code>': </b> the hook is called every time Lua returns from a function;</li> |
|
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|
9665 <li><b>'<code>l</code>': </b> the hook is called every time Lua enters a new line of code.</li> |
|
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|
9666 </ul><p> |
|
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|
9667 Moreover, |
|
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changeset
|
9668 with a <code>count</code> different from zero, |
|
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|
9669 the hook is called also after every <code>count</code> instructions. |
|
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changeset
|
9670 |
|
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Franklin Schmidt <fschmidt@gmail.com>
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diff
changeset
|
9671 |
|
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Franklin Schmidt <fschmidt@gmail.com>
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|
9672 <p> |
|
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|
9673 When called without arguments, |
|
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|
9674 <a href="#pdf-debug.sethook"><code>debug.sethook</code></a> turns off the hook. |
|
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changeset
|
9675 |
|
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changeset
|
9676 |
|
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|
9677 <p> |
|
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|
9678 When the hook is called, its first parameter is a string |
|
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|
9679 describing the event that has triggered its call: |
|
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|
9680 <code>"call"</code> (or <code>"tail call"</code>), |
|
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|
9681 <code>"return"</code>, |
|
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|
9682 <code>"line"</code>, and <code>"count"</code>. |
|
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|
9683 For line events, |
|
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|
9684 the hook also gets the new line number as its second parameter. |
|
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changeset
|
9685 Inside a hook, |
|
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|
9686 you can call <code>getinfo</code> with level 2 to get more information about |
|
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changeset
|
9687 the running function |
|
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|
9688 (level 0 is the <code>getinfo</code> function, |
|
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|
9689 and level 1 is the hook function). |
|
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changeset
|
9690 |
|
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changeset
|
9691 |
|
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Franklin Schmidt <fschmidt@gmail.com>
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diff
changeset
|
9692 |
|
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Franklin Schmidt <fschmidt@gmail.com>
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changeset
|
9693 |
|
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|
9694 <p> |
|
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|
9695 <hr><h3><a name="pdf-debug.setlocal"><code>debug.setlocal ([thread,] level, local, value)</code></a></h3> |
|
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|
9696 |
|
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changeset
|
9697 |
|
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|
9698 <p> |
|
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|
9699 This function assigns the value <code>value</code> to the local variable |
|
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|
9700 with index <code>local</code> of the function at level <code>level</code> of the stack. |
|
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|
9701 The function returns <b>nil</b> if there is no local |
|
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changeset
|
9702 variable with the given index, |
|
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|
9703 and raises an error when called with a <code>level</code> out of range. |
|
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|
9704 (You can call <code>getinfo</code> to check whether the level is valid.) |
|
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|
9705 Otherwise, it returns the name of the local variable. |
|
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changeset
|
9706 |
|
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changeset
|
9707 |
|
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|
9708 <p> |
|
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|
9709 See <a href="#pdf-debug.getlocal"><code>debug.getlocal</code></a> for more information about |
|
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changeset
|
9710 variable indices and names. |
|
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changeset
|
9711 |
|
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changeset
|
9712 |
|
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changeset
|
9713 |
|
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changeset
|
9714 |
|
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|
9715 <p> |
|
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|
9716 <hr><h3><a name="pdf-debug.setmetatable"><code>debug.setmetatable (value, table)</code></a></h3> |
|
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changeset
|
9717 |
|
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changeset
|
9718 |
|
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|
9719 <p> |
|
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|
9720 Sets the metatable for the given <code>value</code> to the given <code>table</code> |
|
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|
9721 (which can be <b>nil</b>). |
|
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|
9722 Returns <code>value</code>. |
|
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changeset
|
9723 |
|
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changeset
|
9724 |
|
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changeset
|
9725 |
|
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changeset
|
9726 |
|
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|
9727 <p> |
|
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|
9728 <hr><h3><a name="pdf-debug.setupvalue"><code>debug.setupvalue (f, up, value)</code></a></h3> |
|
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changeset
|
9729 |
|
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changeset
|
9730 |
|
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changeset
|
9731 <p> |
|
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changeset
|
9732 This function assigns the value <code>value</code> to the upvalue |
|
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|
9733 with index <code>up</code> of the function <code>f</code>. |
|
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|
9734 The function returns <b>nil</b> if there is no upvalue |
|
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|
9735 with the given index. |
|
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|
9736 Otherwise, it returns the name of the upvalue. |
|
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changeset
|
9737 |
|
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changeset
|
9738 |
|
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changeset
|
9739 |
|
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changeset
|
9740 |
|
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|
9741 <p> |
|
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|
9742 <hr><h3><a name="pdf-debug.setuservalue"><code>debug.setuservalue (udata, value)</code></a></h3> |
|
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changeset
|
9743 |
|
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|
9744 |
|
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|
9745 <p> |
|
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|
9746 Sets the given <code>value</code> as |
|
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|
9747 the Lua value associated to the given <code>udata</code>. |
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|
9748 <code>udata</code> must be a full userdata. |
|
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|
9749 |
|
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|
9750 |
|
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|
9751 <p> |
|
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|
9752 Returns <code>udata</code>. |
|
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|
9753 |
|
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|
9754 |
|
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diff
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|
9755 |
|
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|
9756 |
|
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|
9757 <p> |
|
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|
9758 <hr><h3><a name="pdf-debug.traceback"><code>debug.traceback ([thread,] [message [, level]])</code></a></h3> |
|
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|
9759 |
|
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|
9760 |
|
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|
9761 <p> |
|
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|
9762 If <code>message</code> is present but is neither a string nor <b>nil</b>, |
|
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|
9763 this function returns <code>message</code> without further processing. |
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9764 Otherwise, |
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|
9765 it returns a string with a traceback of the call stack. |
|
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9766 The optional <code>message</code> string is appended |
|
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9767 at the beginning of the traceback. |
|
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9768 An optional <code>level</code> number tells at which level |
|
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|
9769 to start the traceback |
|
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|
9770 (default is 1, the function calling <code>traceback</code>). |
|
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|
9771 |
|
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|
9772 |
|
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|
9773 |
|
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|
9774 |
|
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|
9775 <p> |
|
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|
9776 <hr><h3><a name="pdf-debug.upvalueid"><code>debug.upvalueid (f, n)</code></a></h3> |
|
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|
9777 |
|
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|
9778 |
|
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|
9779 <p> |
|
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|
9780 Returns a unique identifier (as a light userdata) |
|
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9781 for the upvalue numbered <code>n</code> |
|
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|
9782 from the given function. |
|
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|
9783 |
|
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|
9784 |
|
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|
9785 <p> |
|
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|
9786 These unique identifiers allow a program to check whether different |
|
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|
9787 closures share upvalues. |
|
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|
9788 Lua closures that share an upvalue |
|
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|
9789 (that is, that access a same external local variable) |
|
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|
9790 will return identical ids for those upvalue indices. |
|
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|
9791 |
|
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|
9792 |
|
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|
9793 |
|
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|
9794 |
|
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|
9795 <p> |
|
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|
9796 <hr><h3><a name="pdf-debug.upvaluejoin"><code>debug.upvaluejoin (f1, n1, f2, n2)</code></a></h3> |
|
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|
9797 |
|
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|
9798 |
|
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|
9799 <p> |
|
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|
9800 Make the <code>n1</code>-th upvalue of the Lua closure <code>f1</code> |
|
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|
9801 refer to the <code>n2</code>-th upvalue of the Lua closure <code>f2</code>. |
|
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|
9802 |
|
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|
9803 |
|
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|
9804 |
|
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|
9805 |
|
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|
9806 |
|
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|
9807 |
|
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|
9808 |
|
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|
9809 <h1>7 – <a name="7">Lua Standalone</a></h1> |
|
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|
9810 |
|
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|
9811 <p> |
|
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|
9812 Although Lua has been designed as an extension language, |
|
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|
9813 to be embedded in a host C program, |
|
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|
9814 it is also frequently used as a standalone language. |
|
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|
9815 An interpreter for Lua as a standalone language, |
|
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|
9816 called simply <code>lua</code>, |
|
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|
9817 is provided with the standard distribution. |
|
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|
9818 The standalone interpreter includes |
|
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|
9819 all standard libraries, including the debug library. |
|
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|
9820 Its usage is: |
|
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|
9821 |
|
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|
9822 <pre> |
|
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|
9823 lua [options] [script [args]] |
|
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|
9824 </pre><p> |
|
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|
9825 The options are: |
|
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|
9826 |
|
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|
9827 <ul> |
|
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|
9828 <li><b><code>-e <em>stat</em></code>: </b> executes string <em>stat</em>;</li> |
|
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|
9829 <li><b><code>-l <em>mod</em></code>: </b> "requires" <em>mod</em>;</li> |
|
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|
9830 <li><b><code>-i</code>: </b> enters interactive mode after running <em>script</em>;</li> |
|
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|
9831 <li><b><code>-v</code>: </b> prints version information;</li> |
|
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|
9832 <li><b><code>-E</code>: </b> ignores environment variables;</li> |
|
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|
9833 <li><b><code>--</code>: </b> stops handling options;</li> |
|
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|
9834 <li><b><code>-</code>: </b> executes <code>stdin</code> as a file and stops handling options.</li> |
|
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|
9835 </ul><p> |
|
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|
9836 After handling its options, <code>lua</code> runs the given <em>script</em>. |
|
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|
9837 When called without arguments, |
|
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|
9838 <code>lua</code> behaves as <code>lua -v -i</code> |
|
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|
9839 when the standard input (<code>stdin</code>) is a terminal, |
|
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|
9840 and as <code>lua -</code> otherwise. |
|
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|
9841 |
|
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changeset
|
9842 |
|
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|
9843 <p> |
|
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|
9844 When called without option <code>-E</code>, |
|
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|
9845 the interpreter checks for an environment variable <a name="pdf-LUA_INIT_5_3"><code>LUA_INIT_5_3</code></a> |
|
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|
9846 (or <a name="pdf-LUA_INIT"><code>LUA_INIT</code></a> if the versioned name is not defined) |
|
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|
9847 before running any argument. |
|
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|
9848 If the variable content has the format <code>@<em>filename</em></code>, |
|
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|
9849 then <code>lua</code> executes the file. |
|
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|
9850 Otherwise, <code>lua</code> executes the string itself. |
|
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|
9851 |
|
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changeset
|
9852 |
|
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|
9853 <p> |
|
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|
9854 When called with option <code>-E</code>, |
|
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|
9855 besides ignoring <code>LUA_INIT</code>, |
|
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|
9856 Lua also ignores |
|
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|
9857 the values of <code>LUA_PATH</code> and <code>LUA_CPATH</code>, |
|
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changeset
|
9858 setting the values of |
|
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changeset
|
9859 <a href="#pdf-package.path"><code>package.path</code></a> and <a href="#pdf-package.cpath"><code>package.cpath</code></a> |
|
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|
9860 with the default paths defined in <code>luaconf.h</code>. |
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9861 |
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|
9862 |
|
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|
9863 <p> |
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|
9864 All options are handled in order, except <code>-i</code> and <code>-E</code>. |
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|
9865 For instance, an invocation like |
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|
9866 |
|
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|
9867 <pre> |
|
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|
9868 $ lua -e'a=1' -e 'print(a)' script.lua |
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|
9869 </pre><p> |
|
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|
9870 will first set <code>a</code> to 1, then print the value of <code>a</code>, |
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|
9871 and finally run the file <code>script.lua</code> with no arguments. |
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|
9872 (Here <code>$</code> is the shell prompt. Your prompt may be different.) |
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9873 |
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|
9874 |
|
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|
9875 <p> |
|
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|
9876 Before running any code, |
|
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|
9877 <code>lua</code> collects all command-line arguments |
|
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9878 in a global table called <code>arg</code>. |
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9879 The script name goes to index 0, |
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9880 the first argument after the script name goes to index 1, |
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9881 and so on. |
|
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|
9882 Any arguments before the script name |
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9883 (that is, the interpreter name plus its options) |
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9884 go to negative indices. |
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9885 For instance, in the call |
|
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|
9886 |
|
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|
9887 <pre> |
|
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9888 $ lua -la b.lua t1 t2 |
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9889 </pre><p> |
|
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|
9890 the table is like this: |
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|
9891 |
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|
9892 <pre> |
|
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|
9893 arg = { [-2] = "lua", [-1] = "-la", |
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9894 [0] = "b.lua", |
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9895 [1] = "t1", [2] = "t2" } |
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9896 </pre><p> |
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|
9897 If there is no script in the call, |
|
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|
9898 the interpreter name goes to index 0, |
|
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|
9899 followed by the other arguments. |
|
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|
9900 For instance, the call |
|
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|
9901 |
|
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|
9902 <pre> |
|
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|
9903 $ lua -e "print(arg[1])" |
|
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|
9904 </pre><p> |
|
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|
9905 will print "<code>-e</code>". |
|
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|
9906 If there is a script, |
|
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9907 the script is called with parameters |
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|
9908 <code>arg[1]</code>, ···, <code>arg[#arg]</code>. |
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9909 (Like all chunks in Lua, |
|
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|
9910 the script is compiled as a vararg function.) |
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9911 |
|
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|
9912 |
|
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|
9913 <p> |
|
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|
9914 In interactive mode, |
|
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9915 Lua repeatedly prompts and waits for a line. |
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9916 After reading a line, |
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9917 Lua first try to interpret the line as an expression. |
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|
9918 If it succeeds, it prints its value. |
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9919 Otherwise, it interprets the line as a statement. |
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9920 If you write an incomplete statement, |
|
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9921 the interpreter waits for its completion |
|
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9922 by issuing a different prompt. |
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|
9923 |
|
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|
9924 |
|
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9925 <p> |
|
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9926 In case of unprotected errors in the script, |
|
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9927 the interpreter reports the error to the standard error stream. |
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|
9928 If the error object is not a string but |
|
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9929 has a metamethod <code>__tostring</code>, |
|
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9930 the interpreter calls this metamethod to produce the final message. |
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9931 Otherwise, the interpreter converts the error object to a string |
|
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|
9932 and adds a stack traceback to it. |
|
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|
9933 |
|
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|
9934 |
|
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|
9935 <p> |
|
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|
9936 When finishing normally, |
|
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|
9937 the interpreter closes its main Lua state |
|
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|
9938 (see <a href="#lua_close"><code>lua_close</code></a>). |
|
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|
9939 The script can avoid this step by |
|
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|
9940 calling <a href="#pdf-os.exit"><code>os.exit</code></a> to terminate. |
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|
9941 |
|
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|
9942 |
|
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|
9943 <p> |
|
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|
9944 To allow the use of Lua as a |
|
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|
9945 script interpreter in Unix systems, |
|
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|
9946 the standalone interpreter skips |
|
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|
9947 the first line of a chunk if it starts with <code>#</code>. |
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|
9948 Therefore, Lua scripts can be made into executable programs |
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|
9949 by using <code>chmod +x</code> and the <code>#!</code> form, |
|
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|
9950 as in |
|
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|
9951 |
|
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|
9952 <pre> |
|
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|
9953 #!/usr/local/bin/lua |
|
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9954 </pre><p> |
|
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|
9955 (Of course, |
|
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|
9956 the location of the Lua interpreter may be different in your machine. |
|
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|
9957 If <code>lua</code> is in your <code>PATH</code>, |
|
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|
9958 then |
|
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|
9959 |
|
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|
9960 <pre> |
|
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|
9961 #!/usr/bin/env lua |
|
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|
9962 </pre><p> |
|
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|
9963 is a more portable solution.) |
|
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|
9964 |
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|
9965 |
|
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|
9966 |
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|
9967 <h1>8 – <a name="8">Incompatibilities with the Previous Version</a></h1> |
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|
9968 |
|
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|
9969 <p> |
|
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|
9970 Here we list the incompatibilities that you may find when moving a program |
|
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|
9971 from Lua 5.2 to Lua 5.3. |
|
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|
9972 You can avoid some incompatibilities by compiling Lua with |
|
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|
9973 appropriate options (see file <code>luaconf.h</code>). |
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|
9974 However, |
|
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|
9975 all these compatibility options will be removed in the future. |
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|
9976 |
|
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|
9977 |
|
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|
9978 <p> |
|
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|
9979 Lua versions can always change the C API in ways that |
|
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9980 do not imply source-code changes in a program, |
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9981 such as the numeric values for constants |
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9982 or the implementation of functions as macros. |
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9983 Therefore, |
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9984 you should not assume that binaries are compatible between |
|
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9985 different Lua versions. |
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|
9986 Always recompile clients of the Lua API when |
|
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9987 using a new version. |
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9988 |
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9989 |
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9990 <p> |
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9991 Similarly, Lua versions can always change the internal representation |
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9992 of precompiled chunks; |
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9993 precompiled chunks are not compatible between different Lua versions. |
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9994 |
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9995 |
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9996 <p> |
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|
9997 The standard paths in the official distribution may |
|
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9998 change between versions. |
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9999 |
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10000 |
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10001 |
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10002 <h2>8.1 – <a name="8.1">Changes in the Language</a></h2> |
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10003 <ul> |
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10004 |
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10005 <li> |
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10006 The main difference between Lua 5.2 and Lua 5.3 is the |
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10007 introduction of an integer subtype for numbers. |
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10008 Although this change should not affect "normal" computations, |
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10009 some computations |
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10010 (mainly those that involve some kind of overflow) |
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|
10011 can give different results. |
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10012 |
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|
10013 |
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10014 <p> |
|
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|
10015 You can fix these differences by forcing a number to be a float |
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10016 (in Lua 5.2 all numbers were float), |
|
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|
10017 in particular writing constants with an ending <code>.0</code> |
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|
10018 or using <code>x = x + 0.0</code> to convert a variable. |
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|
10019 (This recommendation is only for a quick fix |
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|
10020 for an occasional incompatibility; |
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|
10021 it is not a general guideline for good programming. |
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|
10022 For good programming, |
|
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|
10023 use floats where you need floats |
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|
10024 and integers where you need integers.) |
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|
10025 </li> |
|
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|
10026 |
|
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|
10027 <li> |
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|
10028 The conversion of a float to a string now adds a <code>.0</code> suffix |
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|
10029 to the result if it looks like an integer. |
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|
10030 (For instance, the float 2.0 will be printed as <code>2.0</code>, |
|
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|
10031 not as <code>2</code>.) |
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|
10032 You should always use an explicit format |
|
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|
10033 when you need a specific format for numbers. |
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10034 |
|
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|
10035 |
|
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|
10036 <p> |
|
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|
10037 (Formally this is not an incompatibility, |
|
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|
10038 because Lua does not specify how numbers are formatted as strings, |
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|
10039 but some programs assumed a specific format.) |
|
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|
10040 </li> |
|
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|
10041 |
|
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|
10042 <li> |
|
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|
10043 The generational mode for the garbage collector was removed. |
|
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|
10044 (It was an experimental feature in Lua 5.2.) |
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|
10045 </li> |
|
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changeset
|
10046 |
|
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|
10047 </ul> |
|
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|
10048 |
|
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|
10049 |
|
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|
10050 |
|
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|
10051 |
|
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|
10052 <h2>8.2 – <a name="8.2">Changes in the Libraries</a></h2> |
|
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|
10053 <ul> |
|
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changeset
|
10054 |
|
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|
10055 <li> |
|
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|
10056 The <code>bit32</code> library has been deprecated. |
|
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|
10057 It is easy to require a compatible external library or, |
|
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|
10058 better yet, to replace its functions with appropriate bitwise operations. |
|
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|
10059 (Keep in mind that <code>bit32</code> operates on 32-bit integers, |
|
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|
10060 while the bitwise operators in standard Lua operate on 64-bit integers.) |
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|
10061 </li> |
|
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|
10062 |
|
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|
10063 <li> |
|
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|
10064 The Table library now respects metamethods |
|
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|
10065 for setting and getting elements. |
|
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changeset
|
10066 </li> |
|
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changeset
|
10067 |
|
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|
10068 <li> |
|
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|
10069 The <a href="#pdf-ipairs"><code>ipairs</code></a> iterator now respects metamethods and |
|
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|
10070 its <code>__ipairs</code> metamethod has been deprecated. |
|
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|
10071 </li> |
|
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changeset
|
10072 |
|
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|
10073 <li> |
|
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|
10074 Option names in <a href="#pdf-io.read"><code>io.read</code></a> do not have a starting '<code>*</code>' anymore. |
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|
10075 For compatibility, Lua will continue to ignore this character. |
|
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changeset
|
10076 </li> |
|
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changeset
|
10077 |
|
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|
10078 <li> |
|
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|
10079 The following functions were deprecated in the mathematical library: |
|
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|
10080 <code>atan2</code>, <code>cosh</code>, <code>sinh</code>, <code>tanh</code>, <code>pow</code>, |
|
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|
10081 <code>frexp</code>, and <code>ldexp</code>. |
|
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|
10082 You can replace <code>math.pow(x,y)</code> with <code>x^y</code>; |
|
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|
10083 you can replace <code>math.atan2</code> with <code>math.atan</code>, |
|
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|
10084 which now accepts one or two parameters; |
|
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|
10085 you can replace <code>math.ldexp(x,exp)</code> with <code>x * 2.0^exp</code>. |
|
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|
10086 For the other operations, |
|
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changeset
|
10087 you can either use an external library or |
|
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|
10088 implement them in Lua. |
|
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changeset
|
10089 </li> |
|
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changeset
|
10090 |
|
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|
10091 <li> |
|
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|
10092 The searcher for C loaders used by <a href="#pdf-require"><code>require</code></a> |
|
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|
10093 changed the way it handles versioned names. |
|
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|
10094 Now, the version should come after the module name |
|
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|
10095 (as is usual in most other tools). |
|
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|
10096 For compatibility, that searcher still tries the old format |
|
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changeset
|
10097 if it cannot find an open function according to the new style. |
|
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10098 (Lua 5.2 already worked that way, |
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10099 but it did not document the change.) |
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10100 </li> |
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10101 |
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10102 </ul> |
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10103 |
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10104 |
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10105 |
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10106 |
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10107 <h2>8.3 – <a name="8.3">Changes in the API</a></h2> |
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10108 |
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10109 |
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10110 <ul> |
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10111 |
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10112 <li> |
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10113 Continuation functions now receive as parameters what they needed |
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10114 to get through <code>lua_getctx</code>, |
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10115 so <code>lua_getctx</code> has been removed. |
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10116 Adapt your code accordingly. |
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10117 </li> |
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10118 |
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10119 <li> |
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10120 Function <a href="#lua_dump"><code>lua_dump</code></a> has an extra parameter, <code>strip</code>. |
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10121 Use 0 as the value of this parameter to get the old behavior. |
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10122 </li> |
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10123 |
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10124 <li> |
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10125 Functions to inject/project unsigned integers |
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10126 (<code>lua_pushunsigned</code>, <code>lua_tounsigned</code>, <code>lua_tounsignedx</code>, |
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10127 <code>luaL_checkunsigned</code>, <code>luaL_optunsigned</code>) |
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10128 were deprecated. |
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10129 Use their signed equivalents with a type cast. |
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10130 </li> |
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10131 |
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10132 <li> |
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10133 Macros to project non-default integer types |
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10134 (<code>luaL_checkint</code>, <code>luaL_optint</code>, <code>luaL_checklong</code>, <code>luaL_optlong</code>) |
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10135 were deprecated. |
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10136 Use their equivalent over <a href="#lua_Integer"><code>lua_Integer</code></a> with a type cast |
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10137 (or, when possible, use <a href="#lua_Integer"><code>lua_Integer</code></a> in your code). |
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10138 </li> |
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10139 |
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10140 </ul> |
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10141 |
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10142 |
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10143 |
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10144 |
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10145 <h1>9 – <a name="9">The Complete Syntax of Lua</a></h1> |
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10146 |
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10147 <p> |
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10148 Here is the complete syntax of Lua in extended BNF. |
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10149 As usual in extended BNF, |
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10150 {A} means 0 or more As, |
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10151 and [A] means an optional A. |
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10152 (For operator precedences, see <a href="#3.4.8">§3.4.8</a>; |
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10153 for a description of the terminals |
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10154 Name, Numeral, |
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10155 and LiteralString, see <a href="#3.1">§3.1</a>.) |
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10156 |
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10157 |
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10158 |
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10159 |
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10160 <pre> |
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10161 |
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10162 chunk ::= block |
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10163 |
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10164 block ::= {stat} [retstat] |
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10165 |
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10166 stat ::= ‘<b>;</b>’ | |
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10167 varlist ‘<b>=</b>’ explist | |
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10168 functioncall | |
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10169 label | |
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10170 <b>break</b> | |
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10171 <b>goto</b> Name | |
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10172 <b>do</b> block <b>end</b> | |
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10173 <b>while</b> exp <b>do</b> block <b>end</b> | |
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10174 <b>repeat</b> block <b>until</b> exp | |
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10175 <b>if</b> exp <b>then</b> block {<b>elseif</b> exp <b>then</b> block} [<b>else</b> block] <b>end</b> | |
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10176 <b>for</b> Name ‘<b>=</b>’ exp ‘<b>,</b>’ exp [‘<b>,</b>’ exp] <b>do</b> block <b>end</b> | |
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10177 <b>for</b> namelist <b>in</b> explist <b>do</b> block <b>end</b> | |
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10178 <b>function</b> funcname funcbody | |
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10179 <b>local</b> <b>function</b> Name funcbody | |
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10180 <b>local</b> namelist [‘<b>=</b>’ explist] |
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10181 |
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10182 retstat ::= <b>return</b> [explist] [‘<b>;</b>’] |
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10183 |
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10184 label ::= ‘<b>::</b>’ Name ‘<b>::</b>’ |
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10185 |
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10186 funcname ::= Name {‘<b>.</b>’ Name} [‘<b>:</b>’ Name] |
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10187 |
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10188 varlist ::= var {‘<b>,</b>’ var} |
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10189 |
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10190 var ::= Name | prefixexp ‘<b>[</b>’ exp ‘<b>]</b>’ | prefixexp ‘<b>.</b>’ Name |
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10191 |
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10192 namelist ::= Name {‘<b>,</b>’ Name} |
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10193 |
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10194 explist ::= exp {‘<b>,</b>’ exp} |
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10195 |
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10196 exp ::= <b>nil</b> | <b>false</b> | <b>true</b> | Numeral | LiteralString | ‘<b>...</b>’ | functiondef | |
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10197 prefixexp | tableconstructor | exp binop exp | unop exp |
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10198 |
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10199 prefixexp ::= var | functioncall | ‘<b>(</b>’ exp ‘<b>)</b>’ |
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10200 |
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10201 functioncall ::= prefixexp args | prefixexp ‘<b>:</b>’ Name args |
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10202 |
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10203 args ::= ‘<b>(</b>’ [explist] ‘<b>)</b>’ | tableconstructor | LiteralString |
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10204 |
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10205 functiondef ::= <b>function</b> funcbody |
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10206 |
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10207 funcbody ::= ‘<b>(</b>’ [parlist] ‘<b>)</b>’ block <b>end</b> |
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10208 |
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10209 parlist ::= namelist [‘<b>,</b>’ ‘<b>...</b>’] | ‘<b>...</b>’ |
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10210 |
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10211 tableconstructor ::= ‘<b>{</b>’ [fieldlist] ‘<b>}</b>’ |
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10212 |
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10213 fieldlist ::= field {fieldsep field} [fieldsep] |
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10214 |
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10215 field ::= ‘<b>[</b>’ exp ‘<b>]</b>’ ‘<b>=</b>’ exp | Name ‘<b>=</b>’ exp | exp |
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10216 |
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Franklin Schmidt <fschmidt@gmail.com>
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10217 fieldsep ::= ‘<b>,</b>’ | ‘<b>;</b>’ |
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Franklin Schmidt <fschmidt@gmail.com>
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10218 |
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Franklin Schmidt <fschmidt@gmail.com>
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10219 binop ::= ‘<b>+</b>’ | ‘<b>-</b>’ | ‘<b>*</b>’ | ‘<b>/</b>’ | ‘<b>//</b>’ | ‘<b>^</b>’ | ‘<b>%</b>’ | |
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10220 ‘<b>&</b>’ | ‘<b>~</b>’ | ‘<b>|</b>’ | ‘<b>>></b>’ | ‘<b><<</b>’ | ‘<b>..</b>’ | |
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10221 ‘<b><</b>’ | ‘<b><=</b>’ | ‘<b>></b>’ | ‘<b>>=</b>’ | ‘<b>==</b>’ | ‘<b>~=</b>’ | |
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add manual.html as copy of Lua 5.3 Reference Manual
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10222 <b>and</b> | <b>or</b> |
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Franklin Schmidt <fschmidt@gmail.com>
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10223 |
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10224 unop ::= ‘<b>-</b>’ | <b>not</b> | ‘<b>#</b>’ | ‘<b>~</b>’ |
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10225 |
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10226 </pre> |
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10227 |
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Franklin Schmidt <fschmidt@gmail.com>
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10228 <p> |
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10229 |
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10230 |
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10231 |
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10232 |
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10233 |
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Franklin Schmidt <fschmidt@gmail.com>
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10234 |
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10235 |
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Franklin Schmidt <fschmidt@gmail.com>
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10236 |
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Franklin Schmidt <fschmidt@gmail.com>
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10237 <HR> |
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Franklin Schmidt <fschmidt@gmail.com>
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10238 <SMALL CLASS="footer"> |
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Franklin Schmidt <fschmidt@gmail.com>
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10239 Last update: |
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Franklin Schmidt <fschmidt@gmail.com>
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10240 Fri Jan 16 00:58:20 BRST 2015 |
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10241 </SMALL> |
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10242 <!-- |
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10243 Last change: minor edit |
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Franklin Schmidt <fschmidt@gmail.com>
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10244 --> |
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10245 |
| 372 | 10246 </div> |
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386
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10247 |
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10248 <% end; |
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Franklin Schmidt <fschmidt@gmail.com>
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10249 } |
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10250 end |