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annotate website/src/manual.html.luan @ 1929:31f006c64782
translation
author | Franklin Schmidt <fschmidt@gmail.com> |
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date | Thu, 01 May 2025 18:31:05 -0600 |
parents | 4206242c7a13 |
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rev | line source |
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1656 | 1 local Luan = require "luan:Luan.luan" |
2 local error = Luan.error | |
1929 | 3 local pairs = Luan.pairs or error() |
4 local String = require "luan:String.luan" | |
5 local replace = String.replace or error() | |
6 local Table = require "luan:Table.luan" | |
7 local concat = Table.concat or error() | |
1656 | 8 local Io = require "luan:Io.luan" |
1929 | 9 local Site_translator = require "luan:gpt/Site_translator.luan" |
10 local get_lang = Site_translator.get_lang or error() | |
11 local text_writer = Site_translator.text_writer or error() | |
12 local languages = Site_translator.languages or error() | |
13 local set_translated = Site_translator.set_translated or error() | |
1656 | 14 local Shared = require "site:/lib/Shared.luan" |
15 local head = Shared.head or error() | |
16 local docs_header = Shared.docs_header or error() | |
17 local show_toc = Shared.show_toc or error() | |
18 local show_content = Shared.show_content or error() | |
1929 | 19 local show_content_info = Shared.show_content_info or error() |
20 local Translator = require "luan:gpt/Translator.luan" | |
21 local translate_html = Translator.translate_html or error() | |
22 local Logging = require "luan:logging/Logging.luan" | |
23 local logger = Logging.logger "manual.html" | |
1656 | 24 |
25 | |
26 local content = { | |
27 intro = { | |
28 title = "Introduction" | |
29 content = function() | |
30 %> | |
31 <p> | |
1827 | 32 Luan is a high level programming language based on <a href="https://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. |
1656 | 33 </p> |
34 | |
35 <p> | |
36 Luan is implemented in Java and is tightly coupled with Java. So it makes a great scripting language for Java programmers. | |
37 </p> | |
38 | |
39 <p> | |
40 Unlike Lua which is meant to be embedded, Luan is meant to be a full scripting language. This done not by adding features to Luan, but rather by providing a complete set of libraries. | |
41 </p> | |
42 <% | |
43 end | |
44 } | |
45 basic = { | |
46 title = "Basic Concepts" | |
47 content = function() | |
48 %> | |
49 <p> | |
50 This section describes the basic concepts of the language. | |
51 </p> | |
52 <% | |
53 end | |
54 subs = { | |
55 types = { | |
56 title = "Values and Types" | |
57 content = function() | |
58 %> | |
59 <p> | |
60 Luan is a <em>dynamically typed language</em>. | |
61 This means that | |
62 variables do not have types; only values do. | |
63 There are no type definitions in the language. | |
64 All values carry their own type. | |
65 </p> | |
66 | |
67 <p> | |
68 All values in Luan are <em>first-class values</em>. | |
69 This means that all values can be stored in variables, | |
70 passed as arguments to other functions, and returned as results. | |
71 </p> | |
72 | |
73 <p> | |
74 There are eight basic types in Luan: | |
75 <em>nil</em>, <em>boolean</em>, <em>number</em>, | |
76 <em>string</em>, <em>binary</em>, <em>function</em>, <em>java</em>, | |
77 and <em>table</em>. | |
78 <em>Nil</em> is the type of the value <b>nil</b>, | |
79 whose main property is to be different from any other value; | |
80 it usually represents the absence of a useful value. | |
81 <em>Nil</em> is implemented as the Java value <em>null</em>. | |
82 <em>Boolean</em> is the type of the values <b>false</b> and <b>true</b>. | |
83 <em>Boolean</em> is implemented as the Java class <em>Boolean</em>. | |
84 <em>Number</em> represents both | |
85 integer numbers and real (floating-point) numbers. | |
86 <em>Number</em> is implemented as the Java class <em>Number</em>. Any Java subclass of <em>Number</em> is allowed and this is invisible to the Luan user. Operations on numbers follow the same rules of | |
87 the underlying Java implementation. | |
88 <em>String</em> is implemented as the Java class <em>String</em>. | |
89 <em>Binary</em> is implemented as the Java type <em>byte[]</em>. | |
90 </p> | |
91 | |
92 <p> | |
93 Luan can call (and manipulate) functions written in Luan and | |
94 functions written in Java (see <a href="#fn_calls">Function Calls</a>). | |
95 Both are represented by the type <em>function</em>. | |
96 </p> | |
97 | |
98 <p> | |
99 The type <em>java</em> is provided to allow arbitrary Java objects to | |
100 be stored in Luan variables. | |
101 A <em>java</em> value is a Java object that isn't one of the standard Luan types. | |
102 Java values have no predefined operations in Luan, | |
103 except assignment and identity test. | |
104 Java values are useful when Java access is enabled in Luan. | |
105 </p> | |
106 | |
107 <p> | |
108 The type <em>table</em> implements associative arrays, | |
109 that is, arrays that can be indexed not only with numbers, | |
110 but with any Luan value except <b>nil</b>. | |
111 Tables can be <em>heterogeneous</em>; | |
112 that is, they can contain values of all types (except <b>nil</b>). | |
113 Any key with value <b>nil</b> is not considered part of the table. | |
114 Conversely, any key that is not part of a table has | |
115 an associated value <b>nil</b>. | |
116 </p> | |
117 | |
118 <p> | |
119 Tables are the sole data-structuring mechanism in Luan; | |
120 they can be used to represent ordinary arrays, sequences, | |
121 symbol tables, sets, records, graphs, trees, etc. | |
122 To represent records, Luan uses the field name as an index. | |
123 The language supports this representation by | |
124 providing <code>a.name</code> as syntactic sugar for <code>a["name"]</code>. | |
125 There are several convenient ways to create tables in Luan | |
126 (see <a href="#constructors">Table Constructors</a>). | |
127 </p> | |
128 | |
129 <p> | |
130 We use the term <em>sequence</em> to denote a table where | |
131 the set of all positive numeric keys is equal to {1..<em>n</em>} | |
132 for some non-negative integer <em>n</em>, | |
133 which is called the length of the sequence (see <a href="#length">The Length Operator</a>). | |
134 </p> | |
135 | |
136 <p> | |
137 Like indices, | |
138 the values of table fields can be of any type. | |
139 In particular, | |
140 because functions are first-class values, | |
141 table fields can contain functions. | |
142 Thus tables can also carry <em>methods</em> (see <a href="#fn_def">Function Definitions</a>). | |
143 </p> | |
144 | |
145 <p> | |
146 The indexing of tables follows | |
147 the definition of raw equality in the language. | |
148 The expressions <code>a[i]</code> and <code>a[j]</code> | |
149 denote the same table element | |
150 if and only if <code>i</code> and <code>j</code> are raw equal | |
151 (that is, equal without metamethods). | |
152 In particular, floats with integral values | |
153 are equal to their respective integers | |
154 (e.g., <code>1.0 == 1</code>). | |
155 </p> | |
156 | |
157 <p> | |
158 Luan values are <em>objects</em>: | |
159 variables do not actually <em>contain</em> values, | |
160 only <em>references</em> to them. | |
161 Assignment, parameter passing, and function returns | |
162 always manipulate references to values; | |
163 these operations do not imply any kind of copy. | |
164 </p> | |
165 | |
166 <p> | |
167 The library function <a href="#Luan.type"><code>Luan.type</code></a> returns a string describing the type | |
168 of a given value. | |
169 </p> | |
170 <% | |
171 end | |
172 } | |
173 env = { | |
174 title = "Environments" | |
175 content = function() | |
176 %> | |
177 <p> | |
1929 | 178 The environment of a chunk starts with only one local variable: <code><a href="#require">require</a></code>. This function is used to load and access libraries and other modules. All other variables must be added to the environment using <a href="manual.html#local_stmt">local declarations</a>. |
1656 | 179 </p> |
180 | |
181 <p> | |
182 As will be discussed in <a href="#vars">Variables</a> and <a href=#assignment">Assignment</a>, | |
183 any reference to a free name | |
184 (that is, a name not bound to any declaration) <code>var</code> | |
185 can be syntactically translated to <code>_ENV.var</code> if <code>_ENV</code> is defined. | |
186 </p> | |
187 <% | |
188 end | |
189 } | |
190 error = { | |
191 title = "Error Handling" | |
192 content = function() | |
193 %> | |
194 <p> | |
195 Luan code can explicitly generate an error by calling the | |
196 <a href="#Luan.error"><code>error</code></a> function. | |
197 If you need to catch errors in Luan, | |
198 you can use the <a href="#try">Try Statement</code></a>. | |
199 </p> | |
200 | |
201 <p> | |
202 Whenever there is an error, | |
203 an <em>error table</em> | |
204 is propagated with information about the error. | |
205 See <a href="#Luan.new_error"><code>Luan.new_error</code></a>. | |
206 </p> | |
207 <% | |
208 end | |
209 } | |
210 meta = { | |
211 title = "Metatables and Metamethods" | |
212 content = function() | |
213 %> | |
214 <p> | |
215 Every table in Luan can have a <em>metatable</em>. | |
216 This <em>metatable</em> is an ordinary Luan table | |
217 that defines the behavior of the original value | |
218 under certain special operations. | |
219 You can change several aspects of the behavior | |
220 of operations over a value by setting specific fields in its metatable. | |
221 For instance, when a table is the operand of an addition, | |
222 Luan checks for a function in the field "<code>__add</code>" of the table's metatable. | |
223 If it finds one, | |
224 Luan calls this function to perform the addition. | |
225 </p> | |
226 | |
227 <p> | |
228 The keys in a metatable are derived from the <em>event</em> names; | |
229 the corresponding values are called <ii>metamethods</em>. | |
230 In the previous example, the event is <code>"add"</code> | |
231 and the metamethod is the function that performs the addition. | |
232 </p> | |
233 | |
234 <p> | |
235 You can query the metatable of any table | |
236 using the <a href="#Luan.get_metatable"><code>get_metatable</code></a> function. | |
237 </p> | |
238 | |
239 <p> | |
240 You can replace the metatable of tables | |
241 using the <a href="#Luan.set_metatable"><code>set_metatable</code></a> function. | |
242 </p> | |
243 | |
244 <p> | |
245 A metatable controls how a table behaves in | |
246 arithmetic operations, bitwise operations, | |
247 order comparisons, concatenation, length operation, calls, and indexing. | |
248 </p> | |
249 | |
250 <p> | |
251 A detailed list of events controlled by metatables is given next. | |
252 Each operation is identified by its corresponding event name. | |
253 The key for each event is a string with its name prefixed by | |
254 two underscores, '<code>__</code>'; | |
255 for instance, the key for operation "add" is the | |
256 string "<code>__add</code>". | |
257 Note that queries for metamethods are always raw; | |
258 the access to a metamethod does not invoke other metamethods. | |
259 You can emulate how Luan queries a metamethod for an object <code>obj</code> | |
260 with the following code: | |
261 </p> | |
262 | |
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263 <code block> |
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264 raw_get(get_metatable(obj) or {}, "__" .. event_name) |
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265 </code> |
1656 | 266 |
267 <p> | |
268 Here are the events: | |
269 </p> | |
270 | |
271 <ul> | |
272 | |
273 <li><p> | |
274 <b>"add": </b> | |
275 the <code>+</code> operation. | |
276 | |
277 If any operand for an addition is a table, | |
278 Luan will try to call a metamethod. | |
279 First, Luan will check the first operand (even if it is valid). | |
280 If that operand does not define a metamethod for the "<code>__add</code>" event, | |
281 then Luan will check the second operand. | |
282 If Luan can find a metamethod, | |
283 it calls the metamethod with the two operands as arguments, | |
284 and the result of the call | |
285 (adjusted to one value) | |
286 is the result of the operation. | |
287 Otherwise, | |
288 it raises an error. | |
289 </p></li> | |
290 | |
291 <li><p> | |
292 <b>"sub": </b> | |
293 the <code>-</code> operation. | |
294 Behavior similar to the "add" operation. | |
295 </li> | |
296 | |
297 <li><p><b>"mul": </b> | |
298 the <code>*</code> operation. | |
299 Behavior similar to the "add" operation. | |
300 </p></li> | |
301 | |
302 <li><p> | |
303 <b>"div": </b> | |
304 the <code>/</code> operation. | |
305 Behavior similar to the "add" operation. | |
306 </p></li> | |
307 | |
308 <li><p> | |
1680 | 309 <b>"idiv": </b> |
310 the <code>//</code> operation. | |
311 Behavior similar to the "add" operation. | |
312 </p></li> | |
313 | |
314 <li><p> | |
1656 | 315 <b>"mod": </b> |
316 the <code>%</code> operation. | |
317 Behavior similar to the "add" operation. | |
318 </p></li> | |
319 | |
320 <li><p> | |
321 <b>"pow": </b> | |
322 the <code>^</code> (exponentiation) operation. | |
323 Behavior similar to the "add" operation. | |
324 </p></li> | |
325 | |
326 <li><p> | |
327 <b>"unm": </b> | |
328 the <code>-</code> (unary minus) operation. | |
329 Behavior similar to the "add" operation. | |
330 </p></li> | |
331 | |
332 <li><p> | |
333 <b>"concat": </b> | |
334 the <code>..</code> (concatenation) operation. | |
335 Behavior similar to the "add" operation. | |
336 </p></li> | |
337 | |
338 <li><p> | |
339 <b>"len": </b> | |
340 the <code>#</code> (length) operation. | |
341 If there is a metamethod, | |
342 Luan calls it with the object as argument, | |
343 and the result of the call | |
344 (always adjusted to one value) | |
345 is the result of the operation. | |
346 If there is no metamethod but the object is a table, | |
347 then Luan uses the table length operation (see <a href="#length">The Length Operator</a>). | |
348 Otherwise, Luan raises an error. | |
349 </p></li> | |
350 | |
351 <li><p> | |
352 <b>"eq": </b> | |
353 the <code>==</code> (equal) operation. | |
354 Behavior similar to the "add" operation, | |
355 except that Luan will try a metamethod only when the values | |
356 being compared are both tables | |
357 and they are not primitively equal. | |
358 The result of the call is always converted to a boolean. | |
359 </p></li> | |
360 | |
361 <li><p> | |
362 <b>"lt": </b> | |
363 the <code><</code> (less than) operation. | |
364 Behavior similar to the "add" operation. | |
365 The result of the call is always converted to a boolean. | |
366 </p></li> | |
367 | |
368 <li><p> | |
369 <b>"le": </b> | |
370 the <code><=</code> (less equal) operation. | |
371 Unlike other operations, | |
372 The less-equal operation can use two different events. | |
373 First, Luan looks for the "<code>__le</code>" metamethod in both operands, | |
374 like in the "lt" operation. | |
375 If it cannot find such a metamethod, | |
376 then it will try the "<code>__lt</code>" event, | |
377 assuming that <code>a <= b</code> is equivalent to <code>not (b < a)</code>. | |
378 As with the other comparison operators, | |
379 the result is always a boolean. | |
380 </p></li> | |
381 | |
382 <li> | |
383 <p> | |
384 <b>"index": </b> | |
385 The indexing access <code>table[key]</code>. | |
386 This event happens | |
387 when <code>key</code> is not present in <code>table</code>. | |
388 The metamethod is looked up in <code>table</code>. | |
389 </p> | |
390 | |
391 <p> | |
392 Despite the name, | |
393 the metamethod for this event can be any type. | |
394 If it is a function, | |
395 it is called with <code>table</code> and <code>key</code> as arguments. | |
396 Otherwise | |
397 the final result is the result of indexing this metamethod object with <code>key</code>. | |
398 (This indexing is regular, not raw, | |
399 and therefore can trigger another metamethod if the metamethod object is a table.) | |
400 </p> | |
401 </li> | |
402 | |
403 <li> | |
404 <p> | |
405 <b>"new_index": </b> | |
406 The indexing assignment <code>table[key] = value</code>. | |
407 Like the index event, | |
408 this event happens when | |
409 when <code>key</code> is not present in <code>table</code>. | |
410 The metamethod is looked up in <code>table</code>. | |
411 </p> | |
412 | |
413 <p> | |
414 Like with indexing, | |
415 the metamethod for this event can be either a function or a table. | |
416 If it is a function, | |
417 it is called with <code>table</code>, <code>key</code>, and <code>value</code> as arguments. | |
418 If it is a table, | |
419 Luan does an indexing assignment to this table with the same key and value. | |
420 (This assignment is regular, not raw, | |
421 and therefore can trigger another metamethod.) | |
422 </p> | |
423 | |
424 <p> | |
425 Whenever there is a "new_index" metamethod, | |
426 Luan does not perform the primitive assignment. | |
427 (If necessary, | |
428 the metamethod itself can call <a href="#Luan.raw_set"><code>raw_set</code></a> | |
429 to do the assignment.) | |
430 </p> | |
431 </li> | |
432 | |
433 <li><p> | |
434 <b>"gc":</b> | |
1816 | 435 This is when a table is garbage collected. When the table's <a href="https://docs.oracle.com/javase/8/docs/api/java/lang/Object.html#finalize--">finalize</a> method is called by the Java garbage collector, if there is a "<code>__gc</code>" metamethod then it is called with the table as a parameter. |
1656 | 436 </p></li> |
437 | |
438 </ul> | |
439 <% | |
440 end | |
441 } | |
442 gc = { | |
443 title = "Garbage Collection" | |
444 content = function() | |
445 %> | |
446 <p> | |
447 Luan uses Java's garbage collection. | |
448 </p> | |
449 <% | |
450 end | |
451 } | |
452 } | |
453 } | |
454 lang = { | |
455 title = "The Language" | |
456 content = function() | |
457 %> | |
458 <p> | |
459 This section describes the lexis, the syntax, and the semantics of Luan. | |
460 In other words, | |
461 this section describes | |
462 which tokens are valid, | |
463 how they can be combined, | |
464 and what their combinations mean. | |
465 </p> | |
466 | |
467 <p> | |
468 Language constructs will be explained using the usual extended BNF notation, | |
469 in which | |
470 {<em>a</em>} means 0 or more <em>a</em>'s, and | |
471 [<em>a</em>] means an optional <em>a</em>. | |
472 Non-terminals are shown like non-terminal, | |
473 keywords are shown like <b>kword</b>, | |
474 and other terminal symbols are shown like ‘<b>=</b>’. | |
475 The complete syntax of Luan can be found in <a href="#9">§9</a> | |
476 at the end of this manual. | |
477 </p> | |
478 <% | |
479 end | |
480 subs = { | |
481 lex = { | |
482 title = "Lexical Conventions" | |
483 content = function() | |
484 %> | |
485 <p> | |
486 Luan ignores spaces and comments | |
487 between lexical elements (tokens), | |
488 except as delimiters between names and keywords. | |
489 Luan considers the end of a line to be the end of a statement. This catches errors and encourages readability. If you want to continue a statement on another line, you can use a backslash followed by a newline which will be treated as white space. | |
490 </p> | |
491 | |
492 <p> | |
493 <em>Names</em> | |
494 (also called <em>identifiers</em>) | |
495 in Luan can be any string of letters, | |
496 digits, and underscores, | |
497 not beginning with a digit. | |
498 Identifiers are used to name variables, table fields, and labels. | |
499 </p> | |
500 | |
501 <p> | |
502 The following <em>keywords</em> are reserved | |
503 and cannot be used as names: | |
504 </p> | |
505 | |
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506 <p list=keywords> |
1656 | 507 <span>and</span> |
508 <span>break</span> | |
509 <span>catch</span> | |
510 <span>continue</span> | |
511 <span>do</span> | |
512 <span>else</span> | |
513 <span>elseif</span> | |
514 <span>end_do</span> | |
515 <span>end_for</span> | |
516 <span>end_function</span> | |
517 <span>end_if</span> | |
518 <span>end_try</span> | |
519 <span>end_while</span> | |
520 <span>false</span> | |
521 <span>finally</span> | |
522 <span>for</span> | |
523 <span>function</span> | |
524 <span>if</span> | |
525 <span>in</span> | |
526 <span>local</span> | |
527 <span>nil</span> | |
528 <span>not</span> | |
529 <span>or</span> | |
530 <span>repeat</span> | |
531 <span>return</span> | |
532 <span>then</span> | |
533 <span>true</span> | |
534 <span>try</span> | |
535 <span>until</span> | |
536 <span>while</span> | |
537 </p> | |
538 | |
539 <p> | |
540 Luan is a case-sensitive language: | |
541 <code>and</code> is a reserved word, but <code>And</code> and <code>AND</code> | |
542 are two different, valid names. | |
543 </p> | |
544 | |
545 <p> | |
546 The following strings denote other tokens: | |
547 </p> | |
548 | |
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549 <p list=tokens> |
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550 <span>+</span> |
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551 <span>-</span> |
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552 <span>*</span> |
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553 <span>/</span> |
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554 <span>//</span> |
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555 <span>%</span> |
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556 <span>^</span> |
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557 <span>#</span> |
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558 <span>&</span> |
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559 <span>~</span> |
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560 <span>|</span> |
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561 <span>==</span> |
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562 <span>~=</span> |
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563 <span><=</span> |
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564 <span>>=</span> |
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565 <span><</span> |
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566 <span>></span> |
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567 <span>=</span> |
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568 <span>(</span> |
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569 <span>)</span> |
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570 <span>{</span> |
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571 <span>}</span> |
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572 <span>[</span> |
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573 <span>]</span> |
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574 <span>;</span> |
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575 <span>,</span> |
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576 <span>.</span> |
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577 <span>..</span> |
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578 <span>...</span> |
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579 <span>%></span> |
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580 <span><%</span> |
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581 <span><%=</span> |
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582 </p> |
1656 | 583 |
584 <p> | |
585 <em>Literal strings</em> | |
586 can be delimited by matching single or double quotes, | |
587 and can contain the following C-like escape sequences: | |
588 '<code>\a</code>' (bell), | |
589 '<code>\b</code>' (backspace), | |
590 '<code>\f</code>' (form feed), | |
591 '<code>\n</code>' (newline), | |
592 '<code>\r</code>' (carriage return), | |
593 '<code>\t</code>' (horizontal tab), | |
594 '<code>\v</code>' (vertical tab), | |
595 '<code>\\</code>' (backslash), | |
596 '<code>\"</code>' (quotation mark [double quote]), | |
597 and '<code>\'</code>' (apostrophe [single quote]). | |
598 A backslash followed by a real newline | |
599 results in a newline in the string. | |
600 The escape sequence '<code>\z</code>' skips the following span | |
601 of white-space characters, | |
602 including line breaks; | |
603 it is particularly useful to break and indent a long literal string | |
604 into multiple lines without adding the newlines and spaces | |
605 into the string contents. | |
606 </p> | |
607 | |
608 <p> | |
609 Luan can specify any character in a literal string by its numerical value. | |
610 This can be done | |
611 with the escape sequence <code>\x<em>XX</em></code>, | |
612 where <em>XX</em> is a sequence of exactly two hexadecimal digits, | |
613 or with the escape sequence <code>\u<em>XXXX</em></code>, | |
614 where <em>XXXX</em> is a sequence of exactly four hexadecimal digits, | |
615 or with the escape sequence <code>\<em>ddd</em></code>, | |
616 where <em>ddd</em> is a sequence of up to three decimal digits. | |
617 (Note that if a decimal escape sequence is to be followed by a digit, | |
618 it must be expressed using exactly three digits.) | |
619 </p> | |
620 | |
621 <p> | |
622 Literal strings can also be defined using a long format | |
623 enclosed by <em>long brackets</em>. | |
624 We define an <em>opening long bracket of level <em>n</em></em> as an opening | |
625 square bracket followed by <em>n</em> equal signs followed by another | |
626 opening square bracket. | |
627 So, an opening long bracket of level 0 is written as <code>[[</code>, | |
628 an opening long bracket of level 1 is written as <code>[=[</code>, | |
629 and so on. | |
630 A <em>closing long bracket</em> is defined similarly; | |
631 for instance, | |
632 a closing long bracket of level 4 is written as <code>]====]</code>. | |
633 A <em>long literal</em> starts with an opening long bracket of any level and | |
634 ends at the first closing long bracket of the same level. | |
635 It can contain any text except a closing bracket of the same level. | |
636 Literals in this bracketed form can run for several lines, | |
637 do not interpret any escape sequences, | |
638 and ignore long brackets of any other level. | |
639 Any kind of end-of-line sequence | |
640 (carriage return, newline, carriage return followed by newline, | |
641 or newline followed by carriage return) | |
642 is converted to a simple newline. | |
643 </p> | |
644 | |
645 <p> | |
646 Any character in a literal string not | |
647 explicitly affected by the previous rules represents itself. | |
648 However, Luan opens files for parsing in text mode, | |
649 and the system file functions may have problems with | |
650 some control characters. | |
651 So, it is safer to represent | |
652 non-text data as a quoted literal with | |
653 explicit escape sequences for non-text characters. | |
654 </p> | |
655 | |
656 <p> | |
657 For convenience, | |
658 when the opening long bracket is immediately followed by a newline, | |
659 the newline is not included in the string. | |
660 As an example | |
661 the five literal strings below denote the same string: | |
662 </p> | |
663 | |
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664 <code block> |
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665 a = 'alo\n123"' |
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666 a = "alo\n123\"" |
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667 a = '\97lo\10\04923"' |
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668 a = [[alo |
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669 123"]] |
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670 a = [==[ |
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671 alo |
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672 123"]==] |
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673 </code> |
1656 | 674 |
675 <p> | |
676 A <em>numerical constant</em> (or <em>numeral</em>) | |
677 can be written with an optional fractional part | |
678 and an optional decimal exponent, | |
679 marked by a letter '<code>e</code>' or '<code>E</code>'. | |
680 Luan also accepts hexadecimal constants, | |
681 which start with <code>0x</code> or <code>0X</code>. | |
682 Hexadecimal constants also accept an optional fractional part | |
683 plus an optional binary exponent, | |
684 marked by a letter '<code>p</code>' or '<code>P</code>'. | |
685 A numeric constant with a fractional dot or an exponent | |
686 denotes a float; | |
687 otherwise it denotes an integer. | |
688 Examples of valid integer constants are | |
689 </p> | |
690 | |
691 <pre> | |
692 3 345 0xff 0xBEBADA | |
693 </pre> | |
694 | |
695 <p> | |
696 Examples of valid float constants are | |
697 </p> | |
698 | |
699 <pre> | |
700 3.0 3.1416 314.16e-2 0.31416E1 34e1 | |
701 0x0.1E 0xA23p-4 0X1.921FB54442D18P+1 | |
702 </pre> | |
703 | |
704 <p> | |
705 A <em>comment</em> starts with a double hyphen (<code>--</code>) | |
706 anywhere outside a string. | |
707 If the text immediately after <code>--</code> is not an opening long bracket, | |
708 the comment is a <em>short comment</em>, | |
709 which runs until the end of the line. | |
710 Otherwise, it is a <em>long comment</em>, | |
711 which runs until the corresponding closing long bracket. | |
712 Long comments are frequently used to disable code temporarily. | |
713 </p> | |
714 <% | |
715 end | |
716 } | |
717 vars = { | |
718 title = "Variables" | |
719 content = function() | |
720 %> | |
721 <p> | |
722 Variables are places that store values. | |
723 There are three kinds of variables in Luan: | |
724 global variables, local variables, and table fields. | |
725 </p> | |
726 | |
727 <p> | |
728 A single name can denote a global variable or a local variable | |
729 (or a function's formal parameter, | |
730 which is a particular kind of local variable): | |
731 </p> | |
732 | |
733 <pre> | |
734 var ::= Name | |
735 </pre> | |
736 | |
737 <p> | |
738 Name denotes identifiers, as defined in <a href="#lex">Lexical Conventions</a>. | |
739 </p> | |
740 | |
741 <p> | |
742 Local variables are <em>lexically scoped</em>: | |
743 local variables can be freely accessed by functions | |
744 defined inside their scope (see <a href="#visibility">Visibility Rules</a>). | |
745 </p> | |
746 | |
747 <p> | |
748 Before the first assignment to a variable, its value is <b>nil</b>. | |
749 </p> | |
750 | |
751 <p> | |
752 Square brackets are used to index a table: | |
753 </p> | |
754 | |
755 <pre> | |
756 var ::= prefixexp ‘<b>[</b>’ exp ‘<b>]</b>’ | |
757 </pre> | |
758 | |
759 <p> | |
760 The meaning of accesses to table fields can be changed via metatables. | |
761 An access to an indexed variable <code>t[i]</code> is equivalent to | |
762 a call <code>gettable_event(t,i)</code>. | |
763 (See <a href="#meta">Metatables and Metamethods</a> for a complete description of the | |
764 <code>gettable_event</code> function. | |
765 This function is not defined or callable in Luan. | |
766 We use it here only for explanatory purposes.) | |
767 </p> | |
768 | |
769 <p> | |
770 The syntax <code>var.Name</code> is just syntactic sugar for | |
771 <code>var["Name"]</code>: | |
772 </p> | |
773 | |
774 <pre> | |
775 var ::= prefixexp ‘<b>.</b>’ Name | |
776 </pre> | |
777 | |
778 <p> | |
779 Global variables are not available by default. To enable global variable, you must define <code>_ENV</code> as a local variable whose value is a table. If <code>_ENV</code> is not defined, then an unrecognized variable name will produce a compile error. If <code>_ENV</code> is defined then an access to an unrecognized variable name will be consider a global variable. So then an acces to global variable <code>x</code> | |
780 is equivalent to <code>_ENV.x</code>. | |
781 Due to the way that chunks are compiled, | |
782 <code>_ENV</code> is never a global name (see <a href="#env">Environments</a>). | |
783 </p> | |
784 <% | |
785 end | |
786 } | |
787 stmt = { | |
788 title = "Statements" | |
789 content = function() | |
790 %> | |
791 <p> | |
792 Luan supports an almost conventional set of statements, | |
793 similar to those in Pascal or C. | |
794 This set includes | |
795 assignments, control structures, function calls, | |
796 and variable declarations. | |
797 </p> | |
798 <% | |
799 end | |
800 subs = { | |
801 blocks = { | |
802 title = "Blocks" | |
803 content = function() | |
804 %> | |
805 <p> | |
806 A block is a list of statements, | |
807 which are executed sequentially: | |
808 </p> | |
809 | |
810 <pre> | |
811 block ::= {stat} | |
812 </pre> | |
813 | |
814 <p> | |
815 Luan has <em>empty statements</em> | |
816 that allow you to separate statements with semicolons, | |
817 start a block with a semicolon | |
818 or write two semicolons in sequence: | |
819 </p> | |
820 | |
821 <pre> | |
822 stat ::= ‘<b>;</b>’ | |
823 </pre> | |
824 | |
825 <p> | |
826 A block can be explicitly delimited to produce a single statement: | |
827 </p> | |
828 | |
829 <pre> | |
830 stat ::= <b>do</b> block end_do | |
831 end_do ::= <b>end_do</b> | <b>end</b> | |
832 </pre> | |
833 | |
834 <p> | |
835 Explicit blocks are useful | |
836 to control the scope of variable declarations. | |
837 Explicit blocks are also sometimes used to | |
838 add a <b>return</b> statement in the middle | |
839 of another block (see <a href="#control">Control Structures</a>). | |
840 </p> | |
841 <% | |
842 end | |
843 } | |
844 chunks = { | |
845 title = "Chunks" | |
846 content = function() | |
847 %> | |
848 <p> | |
849 The unit of compilation of Luan is called a <em>chunk</em>. | |
850 Syntactically, | |
851 a chunk is simply a block: | |
852 </p> | |
853 | |
854 <pre> | |
855 chunk ::= block | |
856 </pre> | |
857 | |
858 <p> | |
859 Luan handles a chunk as the body of an anonymous function | |
860 with a variable number of arguments | |
861 (see <a href="#fn_def">Function Definitions</a>). | |
862 As such, chunks can define local variables, | |
863 receive arguments, and return values. | |
864 </p> | |
865 | |
866 <p> | |
867 A chunk can be stored in a file or in a string inside the host program. | |
868 To execute a chunk, | |
869 Luan first <em>loads</em> it, | |
870 compiling the chunk's code, | |
871 and then Luan executes the compiled code. | |
872 </p> | |
873 <% | |
874 end | |
875 } | |
876 assignment = { | |
877 title = "Assignment" | |
878 content = function() | |
879 %> | |
880 <p> | |
881 Luan allows multiple assignments. | |
882 Therefore, the syntax for assignment | |
883 defines a list of variables on the left side | |
884 and a list of expressions on the right side. | |
885 The elements in both lists are separated by commas: | |
886 </p> | |
887 | |
888 <pre> | |
889 stat ::= varlist ‘<b>=</b>’ explist | |
890 varlist ::= var {‘<b>,</b>’ var} | |
891 explist ::= exp {‘<b>,</b>’ exp} | |
892 </pre> | |
893 | |
894 <p> | |
895 Expressions are discussed in <a href="#expressions">Expressions</a>. | |
896 </p> | |
897 | |
898 <p> | |
899 Before the assignment, | |
900 the list of values is <em>adjusted</em> to the length of | |
901 the list of variables. | |
902 If there are more values than needed, | |
903 the excess values are thrown away. | |
904 If there are fewer values than needed, | |
905 the list is extended with as many <b>nil</b>'s as needed. | |
906 If the list of expressions ends with a function call, | |
907 then all values returned by that call enter the list of values, | |
908 before the adjustment | |
909 (except when the call is enclosed in parentheses; see <a href="#expressions">Expressions</a>). | |
910 </p> | |
911 | |
912 <p> | |
913 The assignment statement first evaluates all its expressions | |
914 and only then the assignments are performed. | |
915 Thus the code | |
916 </p> | |
917 | |
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918 <code block> |
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919 i = 3 |
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920 i, a[i] = i+1, 20 |
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921 </code> |
1656 | 922 |
923 <p> | |
924 sets <code>a[3]</code> to 20, without affecting <code>a[4]</code> | |
925 because the <code>i</code> in <code>a[i]</code> is evaluated (to 3) | |
926 before it is assigned 4. | |
927 Similarly, the line | |
928 </p> | |
929 | |
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930 <code block> |
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931 x, y = y, x |
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932 </code> |
1656 | 933 |
934 <p> | |
935 exchanges the values of <code>x</code> and <code>y</code>, | |
936 and | |
937 </p> | |
938 | |
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939 <code block> |
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940 x, y, z = y, z, x |
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941 </code> |
1656 | 942 |
943 <p> | |
944 cyclically permutes the values of <code>x</code>, <code>y</code>, and <code>z</code>. | |
945 </p> | |
946 | |
947 <p> | |
948 The meaning of assignments to global variables | |
949 and table fields can be changed via metatables. | |
950 An assignment to an indexed variable <code>t[i] = val</code> is equivalent to | |
951 <code>settable_event(t,i,val)</code>. | |
952 (See <a href="#meta">Metatables and Metamethods</a> for a complete description of the | |
953 <code>settable_event</code> function. | |
954 This function is not defined or callable in Luan. | |
955 We use it here only for explanatory purposes.) | |
956 </p> | |
957 | |
958 <p> | |
959 An assignment to a global name <code>x = val</code> | |
960 is equivalent to the assignment | |
961 <code>_ENV.x = val</code> (see <a href="#env">Environments</a>). | |
962 Global names are only available when <code>_ENV</code> is defined. | |
963 </p> | |
964 <% | |
965 end | |
966 } | |
1660 | 967 control = { |
968 title = "Control Structures" | |
969 content = function() | |
970 %> | |
971 <p> | |
972 The control structures | |
973 <b>if</b>, <b>while</b>, and <b>repeat</b> have the usual meaning and | |
974 familiar syntax: | |
975 </p> | |
976 | |
977 <pre> | |
978 stat ::= <b>while</b> exp <b>do</b> block end_while | |
979 stat ::= <b>repeat</b> block <b>until</b> exp | |
980 stat ::= <b>if</b> exp <b>then</b> block {<b>elseif</b> exp <b>then</b> block} [<b>else</b> block] end_if | |
981 end_while ::= <b>end_while</b> | <b>end</b> | |
982 end_if ::= <b>end_if</b> | <b>end</b> | |
983 </pre> | |
984 | |
985 <p> | |
986 Luan also has a <b>for</b> statement (see <a href="#for">For Statement</a>). | |
987 </p> | |
988 | |
989 <p> | |
990 The condition expression of a | |
991 control structure must be a boolean. | |
992 Any other value type will produce an error. | |
993 This helps catch errors and makes code more readable. | |
994 </p> | |
995 | |
996 <p> | |
997 In the <b>repeat</b>–<b>until</b> loop, | |
998 the inner block does not end at the <b>until</b> keyword, | |
999 but only after the condition. | |
1000 So, the condition can refer to local variables | |
1001 declared inside the loop block. | |
1002 </p> | |
1003 | |
1004 <p> | |
1005 The <b>break</b> statement terminates the execution of a | |
1006 <b>while</b>, <b>repeat</b>, or <b>for</b> loop, | |
1007 skipping to the next statement after the loop: | |
1008 </p> | |
1009 | |
1010 <pre> | |
1011 stat ::= <b>break</b> | |
1012 </pre> | |
1013 | |
1014 <p> | |
1015 A <b>break</b> ends the innermost enclosing loop. | |
1016 </p> | |
1017 | |
1018 <p> | |
1019 The <b>continue</b> statement jumps to the beginning of a | |
1020 <b>while</b>, <b>repeat</b>, or <b>for</b> loop for next iteration, | |
1021 skipping the execution of statements inside the body of loop for the current iteration: | |
1022 </p> | |
1023 | |
1024 <pre> | |
1025 stat ::= <b>continue</b> | |
1026 </pre> | |
1027 | |
1028 <p> | |
1029 The <b>return</b> statement is used to return values | |
1030 from a function or a chunk | |
1031 (which is an anonymous function). | |
1032 Functions can return more than one value, | |
1033 so the syntax for the <b>return</b> statement is | |
1034 </p> | |
1035 | |
1036 <pre> | |
1037 stat ::= <b>return</b> [explist] [‘<b>;</b>’] | |
1038 </pre> | |
1039 <% | |
1040 end | |
1041 } | |
1042 ["for"] = { | |
1043 title = "For Statement" | |
1044 content = function() | |
1045 %> | |
1046 <p> | |
1047 The <b>for</b> statement works over functions, | |
1048 called <em>iterators</em>. | |
1049 On each iteration, the iterator function is called to produce a new value, | |
1050 stopping when this new value is <b>nil</b>. | |
1051 The <b>for</b> loop has the following syntax: | |
1052 </p> | |
1053 | |
1054 <pre> | |
1055 stat ::= <b>for</b> namelist <b>in</b> exp <b>do</b> block end_for | |
1056 namelist ::= Name {‘<b>,</b>’ Name} | |
1057 end_for ::= <b>end_for</b> | <b>end</b> | |
1058 </pre> | |
1059 | |
1060 <p> | |
1061 A <b>for</b> statement like | |
1062 </p> | |
1063 | |
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1064 <code block> |
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1065 for <em>var_1</em>, ···, <em>var_n</em> in <em>exp</em> do <em>block</em> end |
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1066 </code> |
1660 | 1067 |
1068 <p> | |
1069 is equivalent to the code: | |
1070 </p> | |
1071 | |
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1072 <code block> |
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1073 do |
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1074 local <em>f</em> = <em>exp</em> |
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1075 while true do |
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1076 local <em>var_1</em>, ···, <em>var_n</em> = <em>f</em>() |
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1077 if <em>var_1</em> == nil then break end |
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1078 <em>block</em> |
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1079 end |
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1080 end |
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1081 </code> |
1660 | 1082 |
1083 <p> | |
1084 Note the following: | |
1085 </p> | |
1086 | |
1087 <ul> | |
1088 <li> | |
1089 <code><em>exp</em></code> is evaluated only once. | |
1090 Its result is an <em>iterator</em> function. | |
1091 </li> | |
1092 <li> | |
1093 <code><em>f</em></code> is an invisible variable. | |
1094 The name is here for explanatory purposes only. | |
1095 </li> | |
1096 <li> | |
1097 You can use <b>break</b> to exit a <b>for</b> loop. | |
1098 </li> | |
1099 <li> | |
1100 The loop variables <code><em>var_i</em></code> are local to the loop; | |
1101 you cannot use their values after the <b>for</b> ends. | |
1102 If you need these values, | |
1103 then assign them to other variables before breaking or exiting the loop. | |
1104 </li> | |
1105 </ul> | |
1106 <% | |
1107 end | |
1108 } | |
1109 ["try"] = { | |
1110 title = "Try Statement" | |
1111 content = function() | |
1112 %> | |
1113 <p> | |
1114 The <b>try</b> statement has the same semantics as in Java. | |
1115 </p> | |
1116 | |
1117 <pre> | |
1118 stat ::= <b>try</b> block [<b>catch</b> Name block] [<b>finally</b> block] end_try | |
1119 end_try ::= <b>end_try</b> | <b>end</b> | |
1120 </pre> | |
1121 <% | |
1122 end | |
1123 } | |
1124 fn_stmt = { | |
1125 title = "Function Calls as Statements" | |
1126 content = function() | |
1127 %> | |
1128 <p> | |
1129 To allow possible side-effects, | |
1130 function calls can be executed as statements: | |
1131 </p> | |
1132 | |
1133 <pre> | |
1134 stat ::= functioncall | |
1135 </pre> | |
1136 | |
1137 <p> | |
1138 In this case, all returned values are thrown away. | |
1139 Function calls are explained in <a href="#fn_calls">Function Calls</a>. | |
1140 </p> | |
1141 <% | |
1142 end | |
1143 } | |
1144 logical_stmt = { | |
1145 title = "Logical Statement" | |
1146 content = function() | |
1147 %> | |
1148 <p> | |
1149 <a href="#logical_ops">Logical expressions</a> can be statements. | |
1150 This is useful in cases like this: | |
1151 </p> | |
1152 | |
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1153 <code block> |
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1154 x==5 or error "x should be 5" |
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1155 </code> |
1660 | 1156 <% |
1157 end | |
1158 } | |
1159 local_stmt = { | |
1160 title = "Local Declarations" | |
1161 content = function() | |
1162 %> | |
1163 <p> | |
1164 Local variables can be declared anywhere inside a block. | |
1165 The declaration can include an initial assignment: | |
1166 </p> | |
1167 | |
1168 <pre> | |
1169 stat ::= <b>local</b> namelist [‘<b>=</b>’ explist] | |
1170 </pre> | |
1171 | |
1172 <p> | |
1173 If present, an initial assignment has the same semantics | |
1174 of a multiple assignment (see <a href="#assignment">Assignment</a>). | |
1175 Otherwise, all variables are initialized with <b>nil</b>. | |
1176 </p> | |
1177 | |
1178 <p> | |
1179 A chunk is also a block (see <a href="#chunks">Chunks</a>), | |
1180 and so local variables can be declared in a chunk outside any explicit block. | |
1181 </p> | |
1182 | |
1183 <p> | |
1184 The visibility rules for local variables are explained in <a href="#visibility">Visibility Rules</a>. | |
1185 </p> | |
1186 <% | |
1187 end | |
1188 } | |
1189 template_stmt = { | |
1190 title = "Template Statements" | |
1191 content = function() | |
1192 %> | |
1827 | 1193 <p>Template statements provide the full equivalent of <a href="https://en.wikipedia.org/wiki/Jakarta_Server_Pages">JSP</a> but in a general way. Template statements write to standard output. For example:</p> |
1660 | 1194 </p> |
1195 | |
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1196 <code block> |
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1197 local name = "Bob" |
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1198 %> |
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1199 Hello <%= name %>! |
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1200 Bye <%= name %>. |
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1201 <% |
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1202 </code> |
1660 | 1203 |
1204 <p> | |
1205 is equivalent to the code: | |
1206 </p> | |
1207 | |
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1208 <code block> |
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1209 local name = "Bob" |
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1210 require("luan:Io.luan").stdout.write( "Hello ", name , "!\nBye ", name , ".\n" ) |
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1211 </code> |
1660 | 1212 <% |
1213 end | |
1214 } | |
1215 } | |
1216 } | |
1217 expressions = { | |
1218 title = "Expressions" | |
1219 content = function() | |
1220 %> | |
1221 <p> | |
1222 The basic expressions in Luan are the following: | |
1223 </p> | |
1224 | |
1225 <pre> | |
1226 exp ::= prefixexp | |
1227 exp ::= <b>nil</b> | <b>false</b> | <b>true</b> | |
1228 exp ::= Numeral | |
1229 exp ::= LiteralString | |
1230 exp ::= functiondef | |
1231 exp ::= tableconstructor | |
1232 exp ::= ‘<b>...</b>’ | |
1233 exp ::= exp binop exp | |
1234 exp ::= unop exp | |
1235 prefixexp ::= var | functioncall | ‘<b>(</b>’ exp ‘<b>)</b>’ | |
1236 </pre> | |
1237 | |
1238 <p> | |
1239 Numerals and literal strings are explained in <a href="#lex">Lexical Conventions</a>; | |
1240 variables are explained in <a href="#vars">Variables</a>; | |
1241 function definitions are explained in <a href="#fn_def">Function Definitions</a>; | |
1242 function calls are explained in <a href="#fn_calls">Function Calls</a>; | |
1243 table constructors are explained in <a href="#constructors">Table Constructors</a>. | |
1244 Vararg expressions, | |
1245 denoted by three dots ('<code>...</code>'), can only be used when | |
1246 directly inside a vararg function; | |
1247 they are explained in <a href="#fn_def">Function Definitions</a>. | |
1248 </p> | |
1249 | |
1250 <p> | |
1251 Binary operators comprise arithmetic operators (see <a href="#arithmetic">Arithmetic Operators</a>), | |
1252 relational operators (see <a href="#relational">Relational Operators</a>), logical operators (see <a href="#logical_ops">Logical Operators</a>), | |
1253 and the concatenation operator (see <a href="#concatenation">Concatenation</a>). | |
1254 Unary operators comprise the unary minus (see <a href="#arithmetic">Arithmetic Operators</a>), | |
1255 the unary logical <b>not</b> (see <a href="#logical_ops">Logical Operators</a>), | |
1256 and the unary <em>length operator</em> (see <a href="#length">The Length Operator</a>). | |
1257 </p> | |
1258 | |
1259 <p> | |
1260 Both function calls and vararg expressions can result in multiple values. | |
1261 If a function call is used as a statement (see <a href="#fn_stmt">Function Calls as Statements</a>), | |
1262 then its return list is adjusted to zero elements, | |
1263 thus discarding all returned values. | |
1264 If an expression is used as the last (or the only) element | |
1265 of a list of expressions, | |
1266 then no adjustment is made | |
1267 (unless the expression is enclosed in parentheses). | |
1268 In all other contexts, | |
1269 Luan adjusts the result list to one element, | |
1270 either discarding all values except the first one | |
1271 or adding a single <b>nil</b> if there are no values. | |
1272 </p> | |
1273 | |
1274 <p> | |
1275 Here are some examples: | |
1276 </p> | |
1277 | |
1278 <pre> | |
1279 f() -- adjusted to 0 results | |
1280 g(f(), x) -- f() is adjusted to 1 result | |
1281 g(x, f()) -- g gets x plus all results from f() | |
1282 a,b,c = f(), x -- f() is adjusted to 1 result (c gets nil) | |
1283 a,b = ... -- a gets the first vararg parameter, b gets | |
1284 -- the second (both a and b can get nil if there | |
1285 -- is no corresponding vararg parameter) | |
1286 | |
1287 a,b,c = x, f() -- f() is adjusted to 2 results | |
1288 a,b,c = f() -- f() is adjusted to 3 results | |
1289 return f() -- returns all results from f() | |
1290 return ... -- returns all received vararg parameters | |
1291 return x,y,f() -- returns x, y, and all results from f() | |
1292 {f()} -- creates a list with all results from f() | |
1293 {...} -- creates a list with all vararg parameters | |
1294 {f(), nil} -- f() is adjusted to 1 result | |
1295 </pre> | |
1296 | |
1297 <p> | |
1298 Any expression enclosed in parentheses always results in only one value. | |
1299 Thus, | |
1300 <code>(f(x,y,z))</code> is always a single value, | |
1301 even if <code>f</code> returns several values. | |
1302 (The value of <code>(f(x,y,z))</code> is the first value returned by <code>f</code> | |
1926 | 1303 or <code>nil</code> if <code>f</code> does not return any values.) |
1660 | 1304 </p> |
1305 <% | |
1306 end | |
1307 subs = { | |
1308 arithmetic = { | |
1309 title = "Arithmetic Operators" | |
1310 content = function() | |
1311 %> | |
1312 <p> | |
1313 Luan supports the following arithmetic operators: | |
1314 </p> | |
1315 | |
1316 <ul> | |
1926 | 1317 <li><b>+</b>: addition</li> |
1318 <li><b>-</b>: subtraction</li> | |
1319 <li><b>*</b>: multiplication</li> | |
1320 <li><b>/</b>: float division</li> | |
1321 <li><b>//</b>: floor division</li> | |
1322 <li><b>%</b>: modulo</li> | |
1323 <li><b>^</b>: exponentiation</li> | |
1324 <li><b>-</b>: unary minus</li> | |
1660 | 1325 </ul> |
1326 | |
1327 <p> | |
1816 | 1328 Addition, subtraction, multiplication, division, and unary minus are the same as these operators in Java. Exponentiation uses Java's <a href="https://docs.oracle.com/javase/8/docs/api/java/lang/Math.html#pow-double-double-">Math.pow</a> function. |
1660 | 1329 </p> |
1330 | |
1331 <p> | |
1680 | 1332 Floor division (//) is a division that rounds the quotient towards minus infinity, that is, the floor of the division of its operands. |
1333 </p> | |
1334 | |
1335 <p> | |
1660 | 1336 Modulo is defined as the remainder of a division |
1337 that rounds the quotient towards minus infinite (floor division). | |
1338 (The Java modulo operator is not used.) | |
1339 </p> | |
1340 <% | |
1341 end | |
1342 } | |
1343 conversions = { | |
1344 title = "Coercions and Conversions" | |
1345 content = function() | |
1346 %> | |
1347 <p> | |
1348 Luan generally avoids automatic conversions. | |
1349 String concatenation automatically converts all of its arguments to strings. | |
1350 </p> | |
1351 | |
1352 <p> | |
1353 Luan provides library functions for explicit type conversions. | |
1354 </p> | |
1355 <% | |
1356 end | |
1357 } | |
1358 relational = { | |
1359 title = "Relational Operators" | |
1360 content = function() | |
1361 %> | |
1362 <p> | |
1363 Luan supports the following relational operators: | |
1364 </p> | |
1365 | |
1366 <ul> | |
1926 | 1367 <li><b>==</b>: equality</li> |
1368 <li><b>~=</b>: inequality</li> | |
1369 <li><b><</b>: less than</li> | |
1370 <li><b>></b>: greater than</li> | |
1371 <li><b><=</b>: less or equal</li> | |
1372 <li><b>>=</b>: greater or equal</li> | |
1660 | 1373 </ul> |
1374 | |
1375 <p> | |
1926 | 1376 These operators always result in <code>false</code> or <code>true</code>. |
1660 | 1377 </p> |
1378 | |
1379 <p> | |
1380 Equality (<code>==</code>) first compares the type of its operands. | |
1926 | 1381 If the types are different, then the result is <code>false</code>. |
1660 | 1382 Otherwise, the values of the operands are compared. |
1383 Strings, numbers, and binary values are compared in the obvious way (by value). | |
1384 </p> | |
1385 | |
1386 <p> | |
1387 Tables | |
1388 are compared by reference: | |
1389 two objects are considered equal only if they are the same object. | |
1390 Every time you create a new table, | |
1391 it is different from any previously existing table. | |
1392 Closures are also compared by reference. | |
1393 </p> | |
1394 | |
1395 <p> | |
1396 You can change the way that Luan compares tables | |
1397 by using the "eq" metamethod (see <a href="#meta">Metatables and Metamethods</a>). | |
1398 </p> | |
1399 | |
1400 <p> | |
1816 | 1401 Java values are compared for equality with the Java <a href="https://docs.oracle.com/javase/8/docs/api/java/lang/Object.html#equals-java.lang.Object-"><code>equals</code></a> method. |
1660 | 1402 </p> |
1403 | |
1404 <p> | |
1405 Equality comparisons do not convert strings to numbers | |
1406 or vice versa. | |
1926 | 1407 Thus, <code>"0"==0</code> evaluates to <code>false</code>, |
1660 | 1408 and <code>t[0]</code> and <code>t["0"]</code> denote different |
1409 entries in a table. | |
1410 </p> | |
1411 | |
1412 <p> | |
1413 The operator <code>~=</code> is exactly the negation of equality (<code>==</code>). | |
1414 </p> | |
1415 | |
1416 <p> | |
1417 The order operators work as follows. | |
1418 If both arguments are numbers, | |
1419 then they are compared following | |
1420 the usual rule for binary operations. | |
1421 Otherwise, if both arguments are strings, | |
1422 then their values are compared according to the current locale. | |
1423 Otherwise, Luan tries to call the "lt" or the "le" | |
1424 metamethod (see <a href="#meta">Metatables and Metamethods</a>). | |
1425 A comparison <code>a > b</code> is translated to <code>b < a</code> | |
1426 and <code>a >= b</code> is translated to <code>b <= a</code>. | |
1427 </p> | |
1428 <% | |
1429 end | |
1430 } | |
1667 | 1431 logical_ops = { |
1432 title = "Logical Operators" | |
1433 content = function() | |
1434 %> | |
1435 <p> | |
1436 The logical operators in Luan are | |
1437 <b>and</b>, <b>or</b>, and <b>not</b>. | |
1438 The <b>and</b> and <b>or</b> operators consider both <b>false</b> and <b>nil</b> as false | |
1439 and anything else as true. | |
1440 Like the control structures (see <a href="#control">Control Structures</a>), | |
1441 the <b>not</b> operator requires a boolean value. | |
1442 </p> | |
1443 | |
1444 <p> | |
1445 The negation operator <b>not</b> always returns <b>false</b> or <b>true</b>. | |
1446 The conjunction operator <b>and</b> returns its first argument | |
1447 if this value is <b>false</b> or <b>nil</b>; | |
1448 otherwise, <b>and</b> returns its second argument. | |
1449 The disjunction operator <b>or</b> returns its first argument | |
1450 if this value is different from <b>nil</b> and <b>false</b>; | |
1451 otherwise, <b>or</b> returns its second argument. | |
1452 Both <b>and</b> and <b>or</b> use short-circuit evaluation; | |
1453 that is, | |
1454 the second operand is evaluated only if necessary. | |
1455 Here are some examples: | |
1456 </p> | |
1457 | |
1458 <pre> | |
1459 10 or 20 --> 10 | |
1460 10 or error() --> 10 | |
1461 nil or "a" --> "a" | |
1462 nil and 10 --> nil | |
1463 false and error() --> false | |
1464 false and nil --> false | |
1465 false or nil --> nil | |
1466 10 and 20 --> 20 | |
1467 </pre> | |
1468 | |
1469 <p> | |
1470 (In this manual, | |
1471 <code>--></code> indicates the result of the preceding expression.) | |
1472 </p> | |
1473 <% | |
1474 end | |
1475 } | |
1476 concatenation = { | |
1477 title = "Concatenation" | |
1478 content = function() | |
1479 %> | |
1480 <p> | |
1481 The string concatenation operator in Luan is | |
1482 denoted by two dots ('<code>..</code>'). | |
1483 All operands are converted to strings. | |
1484 </p> | |
1485 <% | |
1486 end | |
1487 } | |
1488 length = { | |
1489 title = "The Length Operator" | |
1490 content = function() | |
1491 %> | |
1492 <p> | |
1493 The length operator is denoted by the unary prefix operator <code>#</code>. | |
1494 The length of a string is its number of characters. | |
1495 The length of a binary is its number of bytes. | |
1496 </p> | |
1497 | |
1498 <p> | |
1499 A program can modify the behavior of the length operator for | |
1500 any table through the <code>__len</code> metamethod (see <a href="#meta">Metatables and Metamethods</a>). | |
1501 </p> | |
1502 | |
1503 <p> | |
1504 Unless a <code>__len</code> metamethod is given, | |
1505 the length of a table <code>t</code> is defined | |
1506 as the number of elements in <em>sequence</em>, | |
1507 that is, | |
1508 the size of the set of its positive numeric keys is equal to <em>{1..n}</em> | |
1509 for some non-negative integer <em>n</em>. | |
1510 In that case, <em>n</em> is its length. | |
1511 Note that a table like | |
1512 </p> | |
1513 | |
1514 <pre> | |
1515 {10, 20, nil, 40} | |
1516 </pre> | |
1517 | |
1518 <p> | |
1519 has a length of <code>2</code>, because that is the last key in sequence. | |
1520 </p> | |
1521 <% | |
1522 end | |
1523 } | |
1524 precedence = { | |
1525 title = "Precedence" | |
1526 content = function() | |
1527 %> | |
1528 <p> | |
1529 Operator precedence in Luan follows the table below, | |
1530 from lower to higher priority: | |
1531 </p> | |
1532 | |
1533 <pre> | |
1534 or | |
1535 and | |
1536 < > <= >= ~= == | |
1537 .. | |
1538 + - | |
1539 * / % | |
1540 unary operators (not # -) | |
1541 ^ | |
1542 </pre> | |
1543 | |
1544 <p> | |
1545 As usual, | |
1546 you can use parentheses to change the precedences of an expression. | |
1547 The concatenation ('<code>..</code>') and exponentiation ('<code>^</code>') | |
1548 operators are right associative. | |
1549 All other binary operators are left associative. | |
1550 </p> | |
1551 <% | |
1552 end | |
1553 } | |
1554 constructors = { | |
1555 title = "Table Constructors" | |
1556 content = function() | |
1557 %> | |
1558 <p> | |
1559 Table constructors are expressions that create tables. | |
1560 Every time a constructor is evaluated, a new table is created. | |
1561 A constructor can be used to create an empty table | |
1562 or to create a table and initialize some of its fields. | |
1563 The general syntax for constructors is | |
1564 </p> | |
1565 | |
1566 <pre> | |
1567 tableconstructor ::= ‘<b>{</b>’ fieldlist ‘<b>}</b>’ | |
1568 fieldlist ::= [field] {fieldsep [field]} | |
1569 field ::= ‘<b>[</b>’ exp ‘<b>]</b>’ ‘<b>=</b>’ exp | Name ‘<b>=</b>’ exp | exp | |
1570 fieldsep ::= ‘<b>,</b>’ | ‘<b>;</b>’ | <b>end_of_line</b> | |
1571 </pre> | |
1572 | |
1573 <p> | |
1574 Each field of the form <code>[exp1] = exp2</code> adds to the new table an entry | |
1575 with key <code>exp1</code> and value <code>exp2</code>. | |
1576 A field of the form <code>name = exp</code> is equivalent to | |
1577 <code>["name"] = exp</code>. | |
1578 Finally, fields of the form <code>exp</code> are equivalent to | |
1579 <code>[i] = exp</code>, where <code>i</code> are consecutive integers | |
1580 starting with 1. | |
1581 Fields in the other formats do not affect this counting. | |
1582 For example, | |
1583 </p> | |
1584 | |
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1585 <code block> |
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1586 a = { [f(1)] = g; "x", "y"; x = 1, f(x), [30] = 23; 45 } |
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1587 </code> |
1667 | 1588 |
1589 <p> | |
1590 is equivalent to | |
1591 </p> | |
1592 | |
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1593 <code block> |
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1594 do |
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1595 local t = {} |
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1596 t[f(1)] = g |
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1597 t[1] = "x" -- 1st exp |
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1598 t[2] = "y" -- 2nd exp |
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1599 t.x = 1 -- t["x"] = 1 |
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1600 t[3] = f(x) -- 3rd exp |
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1601 t[30] = 23 |
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1602 t[4] = 45 -- 4th exp |
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1603 a = t |
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1604 end |
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1605 </code> |
1667 | 1606 |
1607 <p> | |
1608 The order of the assignments in a constructor is undefined. | |
1609 (This order would be relevant only when there are repeated keys.) | |
1610 </p> | |
1611 | |
1612 <p> | |
1613 If the last field in the list has the form <code>exp</code> | |
1614 and the expression is a function call or a vararg expression, | |
1615 then all values returned by this expression enter the list consecutively | |
1616 (see <a href="#fn_calls">Function Calls</a>). | |
1617 </p> | |
1618 | |
1619 <p> | |
1620 The field list can have an optional trailing separator, | |
1621 as a convenience for machine-generated code. | |
1622 </p> | |
1623 <% | |
1624 end | |
1625 } | |
1626 fn_calls = { | |
1627 title = "Function Calls" | |
1628 content = function() | |
1629 %> | |
1630 <p> | |
1631 A function call in Luan has the following syntax: | |
1632 </p> | |
1633 | |
1634 <pre> | |
1635 functioncall ::= prefixexp args | |
1636 </pre> | |
1637 | |
1638 <p> | |
1639 In a function call, | |
1640 first prefixexp and args are evaluated. | |
1641 The value of prefixexp must have type <em>function</em>. | |
1642 This function is called | |
1643 with the given arguments. | |
1644 </p> | |
1645 | |
1646 <p> | |
1647 Arguments have the following syntax: | |
1648 </p> | |
1649 | |
1650 <pre> | |
1651 args ::= ‘<b>(</b>’ [explist] ‘<b>)</b>’ | |
1652 args ::= tableconstructor | |
1653 args ::= LiteralString | |
1654 </pre> | |
1655 | |
1656 <p> | |
1657 All argument expressions are evaluated before the call. | |
1658 A call of the form <code>f{<em>fields</em>}</code> is | |
1659 syntactic sugar for <code>f({<em>fields</em>})</code>; | |
1660 that is, the argument list is a single new table. | |
1661 A call of the form <code>f'<em>string</em>'</code> | |
1662 (or <code>f"<em>string</em>"</code> or <code>f[[<em>string</em>]]</code>) | |
1663 is syntactic sugar for <code>f('<em>string</em>')</code>; | |
1664 that is, the argument list is a single literal string. | |
1665 </p> | |
1666 <% | |
1667 end | |
1668 } | |
1669 fn_def = { | |
1670 title = "Function Definitions" | |
1671 content = function() | |
1672 %> | |
1673 <p> | |
1674 The syntax for function definition is | |
1675 </p> | |
1676 | |
1677 <pre> | |
1678 functiondef ::= <b>function</b> funcbody | |
1679 funcbody ::= ‘<b>(</b>’ [parlist] ‘<b>)</b>’ block end_function | |
1680 end_function ::= <b>end_function</b> | <b>end</b> | |
1681 </pre> | |
1682 | |
1683 <p> | |
1684 The following syntactic sugar simplifies function definitions: | |
1685 </p> | |
1686 | |
1687 <pre> | |
1688 stat ::= <b>function</b> funcname funcbody | |
1689 stat ::= <b>local</b> <b>function</b> Name funcbody | |
1690 funcname ::= Name {‘<b>.</b>’ Name} [‘<b>:</b>’ Name] | |
1691 </pre> | |
1692 | |
1693 <p> | |
1694 The statement | |
1695 </p> | |
1696 | |
1697 <pre> | |
1698 function f () <em>body</em> end | |
1699 </pre> | |
1700 | |
1701 <p> | |
1702 translates to | |
1703 </p> | |
1704 | |
1705 <pre> | |
1706 f = function () <em>body</em> end | |
1707 </pre> | |
1708 | |
1709 <p> | |
1710 The statement | |
1711 <p> | |
1712 | |
1713 <pre> | |
1714 function t.a.b.c.f () <em>body</em> end | |
1715 </pre> | |
1716 | |
1717 <p> | |
1718 translates to | |
1719 </p> | |
1720 | |
1721 <pre> | |
1722 t.a.b.c.f = function () <em>body</em> end | |
1723 </pre> | |
1724 | |
1725 <p> | |
1726 The statement | |
1727 </p> | |
1728 | |
1729 <pre> | |
1730 local function f () <em>body</em> end | |
1731 </pre> | |
1732 | |
1733 <p> | |
1734 translates to | |
1735 </p> | |
1736 | |
1737 <pre> | |
1738 local f; f = function () <em>body</em> end | |
1739 </pre> | |
1740 | |
1741 <p> | |
1742 not to | |
1743 </p> | |
1744 | |
1745 <pre> | |
1746 local f = function () <em>body</em> end | |
1747 </pre> | |
1748 | |
1749 <p> | |
1750 (This only makes a difference when the body of the function | |
1751 contains references to <code>f</code>.) | |
1752 </p> | |
1753 | |
1754 <p> | |
1755 A function definition is an executable expression, | |
1756 whose value has type <em>function</em>. | |
1757 When Luan precompiles a chunk, | |
1758 all its function bodies are precompiled too. | |
1759 Then, whenever Luan executes the function definition, | |
1760 the function is <em>instantiated</em> (or <em>closed</em>). | |
1761 This function instance (or <em>closure</em>) | |
1762 is the final value of the expression. | |
1763 </p> | |
1764 | |
1765 <p> | |
1766 Parameters act as local variables that are | |
1767 initialized with the argument values: | |
1768 </p> | |
1769 | |
1770 <pre> | |
1771 parlist ::= namelist [‘<b>,</b>’ ‘<b>...</b>’] | ‘<b>...</b>’ | |
1772 </pre> | |
1773 | |
1774 <p> | |
1775 When a function is called, | |
1776 the list of arguments is adjusted to | |
1777 the length of the list of parameters if the list is too short, | |
1778 unless the function is a <em>vararg function</em>, | |
1779 which is indicated by three dots ('<code>...</code>') | |
1780 at the end of its parameter list. | |
1781 A vararg function does not adjust its argument list; | |
1782 instead, it collects all extra arguments and supplies them | |
1783 to the function through a <em>vararg expression</em>, | |
1784 which is also written as three dots. | |
1785 The value of this expression is a list of all actual extra arguments, | |
1786 similar to a function with multiple results. | |
1787 If a vararg expression is used inside another expression | |
1788 or in the middle of a list of expressions, | |
1789 then its return list is adjusted to one element. | |
1790 If the expression is used as the last element of a list of expressions, | |
1791 then no adjustment is made | |
1792 (unless that last expression is enclosed in parentheses). | |
1793 </p> | |
1794 | |
1795 <p> | |
1796 As an example, consider the following definitions: | |
1797 </p> | |
1798 <pre> | |
1799 function f(a, b) end | |
1800 function g(a, b, ...) end | |
1801 function r() return 1,2,3 end | |
1802 </pre> | |
1803 | |
1804 <p> | |
1805 Then, we have the following mapping from arguments to parameters and | |
1806 to the vararg expression: | |
1807 </p> | |
1808 <pre> | |
1812
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1809 CALL PARAMETERS |
1667 | 1810 |
1811 f(3) a=3, b=nil | |
1812 f(3, 4) a=3, b=4 | |
1813 f(3, 4, 5) runtime error | |
1814 f(r(), 10) runtime error | |
1815 f(r()) runtime error | |
1816 | |
1817 g(3) a=3, b=nil, ... --> (nothing) | |
1818 g(3, 4) a=3, b=4, ... --> (nothing) | |
1819 g(3, 4, 5, 8) a=3, b=4, ... --> 5 8 | |
1820 g(5, r()) a=5, b=1, ... --> 2 3 | |
1821 </pre> | |
1822 | |
1823 <p> | |
1824 Results are returned using the <b>return</b> statement (see <a href="#control">Control Structures</a>). | |
1825 If control reaches the end of a function | |
1826 without encountering a <b>return</b> statement, | |
1827 then the function returns with no results. | |
1828 </p> | |
1829 <% | |
1830 end | |
1831 } | |
1797 | 1832 backticks = { |
1833 title = "Backticks" | |
1834 content = function() | |
1835 %> | |
1836 <p> | |
1837 A block between backticks is run and then whatever was sent to standard output is returned as a string. Examples: | |
1838 </p> | |
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1839 <code block> |
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1840 local s = `%>1 + 1 = <%=1+1%><%` |
1797 | 1841 |
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1842 local s = ` fn(whatever) ` |
1797 | 1843 |
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1844 local s = `%> |
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1845 ... |
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1846 <%` |
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1847 </code> |
1797 | 1848 <p> |
1849 Backticks complement <a href="#template_stmt">template statements</a>. | |
1850 </p> | |
1851 <% | |
1852 end | |
1853 } | |
1667 | 1854 } |
1855 } | |
1856 visibility = { | |
1857 title = "Visibility Rules" | |
1858 content = function() | |
1859 %> | |
1860 <p> | |
1861 Luan is a lexically scoped language. | |
1862 The scope of a local variable begins at the first statement after | |
1863 its declaration and lasts until the last non-void statement | |
1864 of the innermost block that includes the declaration. | |
1865 Consider the following example: | |
1866 </p> | |
1812
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1867 <code block> |
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1868 local x = 10 -- global to module |
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1869 do -- new block |
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1870 local x = x -- new 'x', with value 10 |
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1871 print(x) --> 10 |
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1872 x = x+1 |
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1873 do -- another block |
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1874 local x = x+1 -- another 'x' |
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1875 print(x) --> 12 |
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1876 end |
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1877 print(x) --> 11 |
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1878 end |
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1879 print(x) --> 10 (the global one) |
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1880 </code> |
1667 | 1881 |
1882 <p> | |
1883 Notice that, in a declaration like <code>local x = x</code>, | |
1884 the new <code>x</code> being declared is not in scope yet, | |
1885 and so the second <code>x</code> refers to the outside variable. | |
1886 </p> | |
1887 | |
1888 <p> | |
1889 Because of the lexical scoping rules, | |
1890 local variables can be freely accessed by functions | |
1891 defined inside their scope. | |
1892 A local variable used by an inner function is called | |
1893 an <em>upvalue</em>, or <em>external local variable</em>, | |
1894 inside the inner function. | |
1895 </p> | |
1896 | |
1897 <p> | |
1898 Notice that each execution of a <b>local</b> statement | |
1899 defines new local variables. | |
1900 Consider the following example: | |
1901 </p> | |
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1902 |
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1903 <code block> |
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1904 local a = {} |
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1905 local x = 20 |
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1906 for i=1,10 do |
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1907 local y = 0 |
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1908 a[i] = function () y=y+1; return x+y end |
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1909 end |
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1910 </code> |
1667 | 1911 |
1912 <p> | |
1913 The loop creates ten closures | |
1914 (that is, ten instances of the anonymous function). | |
1915 Each of these closures uses a different <code>y</code> variable, | |
1916 while all of them share the same <code>x</code>. | |
1917 </p> | |
1918 <% | |
1919 end | |
1920 } | |
1921 } | |
1922 } | |
1923 libs = { | |
1924 title = "Standard Libraries" | |
1925 content = function() | |
1926 %> | |
1927 <p> | |
1928 The standard Luan libraries provide useful functions | |
1929 that are implemented both in Java and in Luan itself. | |
1930 How each function is implemented shouldn't matter to the user. | |
1931 Some of these functions provide essential services to the language | |
1932 (e.g., <a href="#Luan.type"><code>type</code></a> and <a href="#Luan.get_metatable"><code>get_metatable</code></a>); | |
1933 others provide access to "outside" services (e.g., I/O). | |
1934 </p> | |
1935 <% | |
1936 end | |
1937 subs = { | |
1938 default_lib = { | |
1939 title = "Default Environment" | |
1940 content = function() | |
1941 %> | |
1942 <p> | |
1943 This is provided by default as a local variable for any Luan code as described in <a href="#env">Environments</a>. | |
1944 </p> | |
1945 <% | |
1946 end | |
1947 subs = { | |
1948 require = { | |
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1949 title = "require (mod_uri)" |
1667 | 1950 content = function() |
1951 %> | |
1952 <p> | |
1953 Example use: | |
1954 </p> | |
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1955 <code block> |
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1956 local Table = require "luan:Table.luan" |
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1957 </code> |
1667 | 1958 |
1959 <p> | |
1960 Could be defined as: | |
1961 </p> | |
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1962 <code block> |
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1963 local function require(mod_name) |
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1964 return <a href="#Package.load">Package.load</a>(mod_name) or <a href="#Luan.error">Luan.error</a>("module '"..mod_name.."' not found") |
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1965 end |
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1966 </code> |
1667 | 1967 |
1968 <p> | |
1969 A special case is: | |
1970 </p> | |
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1971 <code block> |
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1972 require "java" |
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1973 </code> |
1667 | 1974 |
1975 <p> | |
1976 This enables Java in the current chunk if that chunk has permission to use Java. If the chunk doesn't have permission to use Java, then an error is thrown. | |
1977 </p> | |
1978 <% | |
1979 end | |
1980 } | |
1981 } | |
1982 } | |
1983 luan_lib = { | |
1984 title = "Basic Functions" | |
1985 content = function() | |
1986 %> | |
1987 <p> | |
1988 Include this library by: | |
1989 </p> | |
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1990 |
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1991 <code block> |
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1992 local Luan = require "luan:Luan.luan" |
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1993 </code> |
1667 | 1994 |
1995 <p> | |
1996 The basic library provides basic functions to Luan that don't depend on other libaries. | |
1997 </p> | |
1998 <% | |
1999 end | |
2000 subs = { | |
1813 | 2001 ["Luan.arg"] = { |
2002 title = "Luan.arg" | |
2003 content = function() | |
2004 %> | |
2005 <p>If Luan was run from the command line then this is a list of the command line arguments. For example if one runs Luan like this:</p> | |
2006 | |
2007 <code block> | |
2008 luan t.luan a b c | |
2009 </code> | |
2010 | |
2011 <p>Then Luan.arg will contain:</p> | |
2012 | |
2013 <code block> | |
2014 { | |
2015 [0] = "t.luan" | |
2016 [1] = "a" | |
2017 [2] = "b" | |
2018 [3] = "c" | |
2019 } | |
2020 </code> | |
2021 | |
2022 <p>And of course <code>#Luan.arg</code> will be <code>3</code>.</p> | |
2023 <% | |
2024 end | |
2025 } | |
1667 | 2026 ["Luan.do_file"] = { |
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2027 title = "Luan.do_file ([uri])" |
1667 | 2028 content = function() |
2029 %> | |
2030 <p> | |
2031 Could be defined as: | |
2032 </p> | |
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2033 <code block> |
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2034 function Luan.do_file(uri) |
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2035 local fn = <a href="#Luan.load_file">Luan.load_file</a>(uri) or <a href="#Luan.error">Luan.error</a>("file '"..uri.."' not found") |
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2036 return fn() |
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2037 end |
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2038 </code> |
1667 | 2039 <% |
2040 end | |
2041 } | |
2042 ["Luan.error"] = { | |
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2043 title = "Luan.error (message)" |
1667 | 2044 content = function() |
2045 %> | |
2046 <p> | |
2047 Throws an error containing the message. | |
2048 </p> | |
2049 | |
2050 <p> | |
2051 Could be defined as: | |
2052 </p> | |
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2053 <code block> |
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2054 function Luan.error(message) |
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2055 <a href="#Luan.new_error">Luan.new_error</a>(message).throw() |
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2056 end |
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2057 </code> |
1667 | 2058 <% |
2059 end | |
2060 } | |
2061 ["Luan.eval"] = { | |
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2062 title = "Luan.eval (text [, source_name [, env]])" |
1667 | 2063 content = function() |
2064 %> | |
2065 <p> | |
2066 Evaluates <code>text</code> as a Luan expression. | |
2067 </p> | |
2068 | |
2069 <p> | |
2070 Could be defined as: | |
2071 </p> | |
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2072 <code block> |
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2073 function Luan.eval(text,source_name, env) |
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2074 return <a href="#Luan.load">Luan.load</a>( "return "..text, source_name or "eval", env )() |
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2075 end |
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2076 </code> |
1667 | 2077 <% |
2078 end | |
2079 } | |
2080 ["Luan.get_metatable"] = { | |
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2081 title = "Luan.get_metatable (table)" |
1667 | 2082 content = function() |
2083 %> | |
2084 <p> | |
2085 If <code>table</code> does not have a metatable, returns <b>nil</b>. | |
2086 Otherwise, | |
2087 if the table's metatable has a <code>"__metatable"</code> field, | |
2088 returns the associated value. | |
2089 Otherwise, returns the metatable of the given table. | |
2090 </p> | |
2091 <% | |
2092 end | |
2093 } | |
2094 ["Luan.hash_code"] = { | |
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2095 title = "Luan.hash_code (v)" |
1667 | 2096 content = function() |
2097 %> | |
2098 <p> | |
2099 Returns the hash code of <code>v</code>. | |
2100 </p> | |
2101 <% | |
2102 end | |
2103 } | |
2104 ["Luan.ipairs"] = { | |
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2105 title = "Luan.ipairs (t)" |
1667 | 2106 content = function() |
2107 %> | |
2108 <p> | |
2109 Returns an iterator function | |
2110 so that the construction | |
2111 </p> | |
2112 <pre> | |
2113 for i,v in ipairs(t) do <em>body</em> end | |
2114 </pre> | |
2115 | |
2116 <p> | |
2117 will iterate over the key–value pairs | |
2118 (<code>1,t[1]</code>), (<code>2,t[2]</code>), ..., | |
2119 up to the first nil value. | |
2120 </p> | |
2121 | |
2122 <p> | |
2123 Could be defined as: | |
2124 </p> | |
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2125 <code block> |
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2126 function Luan.ipairs(t) |
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2127 local i = 0 |
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2128 return function() |
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2129 if i < #t then |
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2130 i = i + 1 |
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2131 return i, t[i] |
1667 | 2132 end |
2133 end | |
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2134 end |
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2135 </code> |
1667 | 2136 <% |
2137 end | |
2138 } | |
2139 ["Luan.load"] = { | |
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2140 title = "Luan.load (text, [source_name [, env [, persist]]])" |
1667 | 2141 content = function() |
2142 %> | |
2143 <p> | |
2144 Loads a chunk. | |
2145 </p> | |
2146 | |
2147 <p> | |
2148 The <code>text</code> is compiled. | |
2149 If there are no syntactic errors, | |
2150 returns the compiled chunk as a function; | |
2151 otherwise, throws an error. | |
2152 </p> | |
2153 | |
2154 <p> | |
2155 The <code>source_name</code> parameter is a string saying where the text came from. It is used to produce error messages. Defaults to "load". | |
2156 </p> | |
2157 | |
2158 <p> | |
2159 If the <code>env</code> parameter is supplied, it becomes the <code>_ENV</code> of the chunk. | |
2160 </p> | |
2161 | |
2162 <p> | |
2163 The <code>persist</code> parameter is a boolean which determines if the compiled code is persistently cached to a temporary file. Defaults to <code>false</code>. | |
2164 </p> | |
2165 <% | |
2166 end | |
2167 } | |
2168 ["Luan.load_file"] = { | |
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2169 title = "Luan.load_file (file_uri)" |
1667 | 2170 content = function() |
2171 %> | |
2172 <p> | |
2173 Similar to <a href="#Luan.load"><code>load</code></a>, | |
2174 but gets the chunk from file <code>file_uri</code>. | |
2175 <code>file_uri</code> can be a string or a uri table. | |
2176 </p> | |
2177 <% | |
2178 end | |
2179 } | |
2180 ["Luan.new_error"] = { | |
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2181 title = "Luan.new_error (message)" |
1667 | 2182 content = function() |
2183 %> | |
2184 <p> | |
2185 Creates a new error table containing the message assigned to "<code>message</code>". The error table also contains a <code>throw</code> function which throws the error. The table also contains a list of stack trace elements where each stack trace element is a table containing "<code>source</code>", "<code>line</code>", and possible "<code>call_to</code>". The table also has a metatable containing "<code>__to_string</code>" to render the error. | |
2186 </p> | |
2187 | |
2188 <p> | |
2189 To print the current stack trace, you could do: | |
2190 </p> | |
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2191 <code block> |
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2192 Io.print( Luan.new_error "stack" ) |
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2193 </code> |
1667 | 2194 <% |
2195 end | |
2196 } | |
2197 ["Luan.pairs"] = { | |
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2198 title = "Luan.pairs (t)" |
1667 | 2199 content = function() |
2200 %> | |
2201 <p> | |
2202 If <code>t</code> has a metamethod <code>__pairs</code>, | |
2203 calls it with <code>t</code> as argument and returns the | |
2204 result from the call. | |
2205 </p> | |
2206 | |
2207 <p> | |
2208 Otherwise, | |
2209 returns a function | |
2210 so that the construction | |
2211 </p> | |
2212 <pre> | |
2213 for k,v in pairs(t) do <em>body</em> end | |
2214 </pre> | |
2215 | |
2216 <p> | |
2217 will iterate over all key–value pairs of table <code>t</code>. | |
2218 </p> | |
2219 <% | |
2220 end | |
2221 } | |
1813 | 2222 ["Luan.parse"] = { |
2223 title = "Luan.parse (s)" | |
2224 content = function() | |
2225 %> | |
2226 <p>This Luan's equivalent to Javascript's JSON.parse(), but for a Luan value. In addition to the usual JSON values, Luan.parse allows long strings and allows specifying numeric types of <i>double</i>, <i>float</i>, <i>integer</i>, and <i>long</i>. For example:</p> | |
2227 | |
2228 <code block> | |
2229 local t = Luan.parse[=[ | |
2230 { | |
2231 nothing = nil | |
2232 t = true | |
2233 f = false | |
2234 s = "string" | |
2235 ls = [[long string]] | |
2236 n = 3 | |
2237 d = double(3) | |
2238 f = float(3) | |
2239 i = integer(3) | |
2240 l = long(3) | |
2241 list = { 1, 2, 3 } | |
2242 table = { | |
2243 one = 1 | |
2244 two = 2 | |
2245 three = 3 | |
2246 } | |
2247 ["ugly-key"] = "something" | |
2248 } | |
2249 ]=] | |
2250 </code> | |
2251 <% | |
2252 end | |
2253 } | |
1667 | 2254 ["Luan.range"] = { |
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2255 title = "Luan.range (start, stop [, step])" |
1667 | 2256 content = function() |
2257 %> | |
2258 <p> | |
2259 Based on <a href="https://docs.python.org/2/library/functions.html#range">the Python range() function</a>, this lets one iterate through a sequence of numbers. | |
2260 </p> | |
2261 | |
2262 <p> | |
2263 Example use: | |
2264 </p> | |
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2265 <code block> |
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2266 for i in range(1,10) do |
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2267 Io.print("count up:",i) |
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2268 end |
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2269 for i in range(10,0,-1) do |
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2270 Io.print("count down:",i) |
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2271 end |
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2272 </code> |
1667 | 2273 |
2274 <p> | |
2275 Could be defined as: | |
2276 </p> | |
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2277 <code block> |
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2278 function Luan.range(start, stop, step) |
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2279 step = step or 1 |
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2280 step == 0 and <a href="#Luan.error">Luan.error</a> "bad argument #3 (step may not be zero)" |
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2281 local i = start |
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2282 return function() |
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2283 if step > 0 and i <= stop or step < 0 and i >= stop then |
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2284 local rtn = i |
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2285 i = i + step |
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2286 return rtn |
1667 | 2287 end |
2288 end | |
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2289 end |
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2290 </code> |
1667 | 2291 <% |
2292 end | |
2293 } | |
2294 ["Luan.raw_equal"] = { | |
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2295 title = "Luan.raw_equal (v1, v2)" |
1667 | 2296 content = function() |
2297 %> | |
2298 <p> | |
2299 Checks whether <code>v1</code> is equal to <code>v2</code>, | |
2300 without invoking any metamethod. | |
2301 Returns a boolean. | |
2302 </p> | |
2303 <% | |
2304 end | |
2305 } | |
2306 ["Luan.raw_get"] = { | |
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2307 title = "Luan.raw_get (table, index)" |
1667 | 2308 content = function() |
2309 %> | |
2310 <p> | |
2311 Gets the real value of <code>table[index]</code>, | |
2312 without invoking any metamethod. | |
2313 <code>table</code> must be a table; | |
2314 <code>index</code> may be any value. | |
2315 </p> | |
2316 <% | |
2317 end | |
2318 } | |
2319 ["Luan.raw_len"] = { | |
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2320 title = "Luan.raw_len (v)" |
1667 | 2321 content = function() |
2322 %> | |
2323 <p> | |
2324 Returns the length of the object <code>v</code>, | |
2325 which must be a table or a string, | |
2326 without invoking any metamethod. | |
2327 Returns an integer. | |
2328 </p> | |
2329 <% | |
2330 end | |
2331 } | |
2332 ["Luan.raw_set"] = { | |
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2333 title = "Luan.raw_set (table, index, value)" |
1667 | 2334 content = function() |
2335 %> | |
2336 <p> | |
2337 Sets the real value of <code>table[index]</code> to <code>value</code>, | |
2338 without invoking any metamethod. | |
2339 <code>table</code> must be a table, | |
2340 <code>index</code> any value different from <b>nil</b>, | |
2341 and <code>value</code> any Luan value. | |
1882 | 2342 Returns the old value of <code>table[index]</code>. |
1667 | 2343 </p> |
2344 <% | |
2345 end | |
2346 } | |
2347 ["Luan.set_metatable"] = { | |
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2348 title = "Luan.set_metatable (table, metatable)" |
1667 | 2349 content = function() |
2350 %> | |
2351 <p> | |
2352 Sets the metatable for the given table. | |
2353 If <code>metatable</code> is <b>nil</b>, | |
2354 removes the metatable of the given table. | |
2355 If the original metatable has a <code>"__metatable"</code> field, | |
2356 raises an error. | |
2357 </p> | |
2358 <% | |
2359 end | |
2360 } | |
2361 ["Luan.stringify"] = { | |
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2362 title = "Luan.stringify (v [,options])" |
1667 | 2363 content = function() |
2364 %> | |
2365 <p> | |
1813 | 2366 This Luan's equivalent to Javascript's JSON.stringify(), but for a Luan value. |
2367 <code>v</code> is a value of any type which is converted to a string that is a Luan expression. <code>options</code> may be a table or a function. If <code>options</code> is a table, it may contain the following flags whose <code>true</code> value means: | |
2368 </p> | |
2369 | |
2370 <ul> | |
2371 <li><b>strict</b> - invalid types throw an error</li> | |
2372 <li><b>number_types</b> - numbers will be wrapped in functions for their type</li> | |
2373 <li><b>compressed</b> - eliminates white space</li> | |
2374 <li><b>inline</b> - on one line</li> | |
2375 <li><b>no_name_keys</b> - forces all keys to be of the form <code>["key"]</code></li> | |
2376 </ul> | |
2377 | |
2378 <p>If <code>options</code> is a function then this function should take an argument <code>stack</code> and return an <code>options</code> table. The <code>stack</code> will be a list of keys indicating where stringify is currently processing. This allows different options to be applied at different places in a data structure.</p> | |
1667 | 2379 <% |
2380 end | |
2381 } | |
2382 ["Luan.to_string"] = { | |
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2383 title = "Luan.to_string (v)" |
1667 | 2384 content = function() |
2385 %> | |
2386 <p> | |
2387 Receives a value of any type and | |
2388 converts it to a string in a human-readable format. | |
2389 </p> | |
2390 | |
2391 <p> | |
2392 If the metatable of <code>v</code> has a <code>"__to_string"</code> field, | |
2393 then <code>to_string</code> calls the corresponding value | |
2394 with <code>v</code> as argument, | |
2395 and uses the result of the call as its result. | |
2396 </p> | |
2397 <% | |
2398 end | |
2399 } | |
2400 ["Luan.type"] = { | |
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2401 title = "Luan.type (v)" |
1667 | 2402 content = function() |
2403 %> | |
2404 <p> | |
2405 Returns the type of its only argument, coded as a string. | |
2406 The possible results of this function are | |
2407 "<code>nil</code>" (a string, not the value <b>nil</b>), | |
2408 "<code>number</code>", | |
2409 "<code>string</code>", | |
2410 "<code>binary</code>", | |
2411 "<code>boolean</code>", | |
2412 "<code>table</code>", | |
2413 "<code>function</code>", | |
2414 and "<code>java</code>". | |
2415 </p> | |
2416 <% | |
2417 end | |
2418 } | |
2419 ["Luan.values"] = { | |
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2420 title = "Luan.values (···)" |
1667 | 2421 content = function() |
2422 %> | |
2423 <p> | |
2424 Returns a function so that the construction | |
2425 </p> | |
2426 <pre> | |
2427 for i, v in Luan.values(···) do <em>body</em> end | |
2428 </pre> | |
2429 | |
2430 <p> | |
2431 will iterate over all values of <code>···</code>. | |
2432 </p> | |
2433 <% | |
2434 end | |
2435 } | |
2436 } | |
2437 } | |
2438 package_lib = { | |
2439 title = "Modules" | |
2440 content = function() | |
2441 %> | |
2442 <p> | |
2443 Include this library by: | |
2444 </p> | |
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2445 <code block> |
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2446 local Package = require "luan:Package.luan" |
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2447 </code> |
1667 | 2448 |
2449 <p> | |
2450 The package library provides basic | |
2451 facilities for loading modules in Luan. | |
2452 </p> | |
2453 <% | |
2454 end | |
2455 subs = { | |
2456 ["Package.load"] = { | |
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2457 title = "Package.load (mod_uri)" |
1667 | 2458 content = function() |
2459 %> | |
2460 <p> | |
2461 Loads the given module. | |
2462 The function starts by looking into the <a href="#Package.loaded"><code>Package.loaded</code></a> table | |
2463 to determine whether <code>mod_uri</code> is already loaded. | |
2464 If it is, then <code>Package.load</code> returns the value stored | |
2465 at <code>Package.loaded[mod_uri]</code>. | |
2466 Otherwise, it tries to load a new value for the module. | |
2467 </p> | |
2468 | |
2469 <p> | |
2470 To load a new value, <code>Package.load</code> first checks if <code>mod_uri</code> starts with "<b>java:</b>". If yes, then this is a Java class which is loaded by special Java code. | |
2471 </p> | |
2472 | |
2473 <p> | |
2474 Otherwise <code>Package.load</code> tries to read the text of the file referred to by <code>mod_uri</code>. If the file doesn't exist, then <code>Package.load</code> returns <b>false</b>. If the file exists, then its content is compiled into a chunk by calling <a href="#Luan.load"><code>Luan.load</code></a>. This chunk is run passing in <code>mod_uri</code> as an argument. The value returned by the chunk must not be <b>nil</b> and is loaded. | |
2475 </p> | |
2476 | |
2477 <p> | |
2478 If a new value for the module successful loaded, then it is stored in <code>Package.loaded[mod_uri]</code>. The value is returned. | |
2479 </p> | |
2480 <% | |
2481 end | |
2482 } | |
2483 ["Package.loaded"] = { | |
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2484 title = "Package.loaded" |
1667 | 2485 content = function() |
2486 %> | |
2487 <p> | |
2488 A table used by <a href="#Package.load"><code>Package.load</code></a> to control which | |
2489 modules are already loaded. | |
2490 When you load a module <code>mod_uri</code> and | |
2491 <code>Package.loaded[mod_uri]</code> is not <b>nil</b>, | |
2492 <a href="#Package.load"><code>Package.load</code></a> simply returns the value stored there. | |
2493 </p> | |
2494 | |
2495 <p> | |
2496 This variable is only a reference to the real table; | |
2497 assignments to this variable do not change the | |
2498 table used by <a href="#Package.load"><code>Package.load</code></a>. | |
2499 </p> | |
2500 <% | |
2501 end | |
2502 } | |
1656 | 2503 } |
2504 } | |
1668 | 2505 string_lib = { |
2506 title = "String Manipulation" | |
2507 content = function() | |
2508 %> | |
2509 <p> | |
2510 Include this library by: | |
2511 </p> | |
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2512 <code block> |
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2513 local String = require "luan:String.luan" |
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2514 </code> |
1668 | 2515 |
2516 <p> | |
2517 This library provides generic functions for string manipulation, | |
2518 such as finding and extracting substrings, and pattern matching. | |
2519 When indexing a string in Luan, the first character is at position 1 | |
2520 (not at 0, as in Java). | |
2521 Indices are allowed to be negative and are interpreted as indexing backwards, | |
2522 from the end of the string. | |
2523 Thus, the last character is at position -1, and so on. | |
2524 </p> | |
2525 <% | |
2526 end | |
2527 subs = { | |
2528 ["String.char"] = { | |
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2529 title = "String.char (···)" |
1668 | 2530 content = function() |
2531 %> | |
2532 <p> | |
2533 Receives zero or more integers. | |
2534 Returns a string with length equal to the number of arguments, | |
2535 in which each character has the internal numerical code equal | |
2536 to its corresponding argument. | |
2537 </p> | |
2538 <% | |
2539 end | |
2540 } | |
1716 | 2541 ["String.contains"] = { |
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2542 title = "String.contains (s, s2)" |
1716 | 2543 content = function() |
2544 %> | |
2545 <p> | |
2546 Returns a boolean indicating whether the <code>s</code> contains <code>s2</code>. | |
2547 </p> | |
2548 <% | |
2549 end | |
2550 } | |
1816 | 2551 ["String.digest_message"] = { |
2552 title = "String.digest_message (algorithm, s)" | |
2553 content = function() | |
2554 %> | |
2555 <p>Returns a hex digest string of <code>s</code>. Could be defined as:</p> | |
2556 | |
2557 <code block> | |
2558 function String.digest_message(algorithm,s) | |
1929 | 2559 return <a href="manual.html#Binary.to_hex">Binary.to_hex</a>( <a href="manual.html#Binary.digest_message">Binary.digest_message</a>( algorithm, <a href="manual.html#String.to_binary">String.to_binary(s)</a> ) ) |
1816 | 2560 end |
2561 </code> | |
2562 <% | |
2563 end | |
2564 } | |
1668 | 2565 ["String.encode"] = { |
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2566 title = "String.encode (s)" |
1668 | 2567 content = function() |
2568 %> | |
2569 <p> | |
2570 Encodes argument <code>s</code> into a string that can be placed in quotes so as to return the original value of the string. | |
2571 </p> | |
2572 <% | |
2573 end | |
2574 } | |
1716 | 2575 ["String.ends_with"] = { |
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2576 title = "String.ends_with (s, s2)" |
1716 | 2577 content = function() |
2578 %> | |
2579 <p> | |
2580 Returns a boolean indicating whether the <code>s</code> ends with <code>s2</code>. | |
2581 </p> | |
2582 <% | |
2583 end | |
2584 } | |
1668 | 2585 ["String.find"] = { |
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2586 title = "String.find (s, s2 [, init])" |
1668 | 2587 content = function() |
2588 %> | |
2589 <p> | |
1721
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2590 Looks for the first substring |
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2591 <code>s2</code> in the string <code>s</code>. |
1881 | 2592 If it finds a match, then <code>find</code> returns the index of <code>s</code> |
2593 where this occurrence starts; | |
1668 | 2594 otherwise, it returns <b>nil</b>. |
2595 A third, optional numerical argument <code>init</code> specifies | |
2596 where to start the search; | |
1881 | 2597 its default value is 1 and can be negative. |
2598 </p> | |
2599 <% | |
2600 end | |
2601 } | |
2602 ["String.find_reverse"] = { | |
2603 title = "String.find_reverse (s, s2 [, init])" | |
2604 content = function() | |
2605 %> | |
2606 <p> | |
2607 Looks for the last substring | |
2608 <code>s2</code> in the string <code>s</code>. | |
2609 If it finds a match, then <code>find</code> returns the index of <code>s</code> | |
2610 where this occurrence starts; | |
2611 otherwise, it returns <b>nil</b>. | |
2612 A third, optional numerical argument <code>init</code> specifies | |
2613 where to start the search; | |
2614 its default value is -1. | |
1668 | 2615 </p> |
2616 <% | |
2617 end | |
2618 } | |
2619 ["String.format"] = { | |
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2620 title = "String.format (formatstring, ···)" |
1668 | 2621 content = function() |
2622 %> | |
2623 <p> | |
2624 Returns a formatted version of its variable number of arguments | |
2625 following the description given in its first argument (which must be a string). | |
1816 | 2626 The format string follows the same rules as the Java function <a href="https://docs.oracle.com/javase/8/docs/api/java/lang/String.html#format-java.lang.String-java.lang.Object...-"><code>String.format</code></a> because Luan calls this internally. |
1668 | 2627 </p> |
2628 | |
2629 <p> | |
2630 Note that Java's <code>String.format</code> is too stupid to convert between ints and floats, so you must provide the right kind of number. | |
2631 </p> | |
2632 <% | |
2633 end | |
2634 } | |
2635 ["String.lower"] = { | |
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2636 title = "String.lower (s)" |
1668 | 2637 content = function() |
2638 %> | |
2639 <p> | |
2640 Receives a string and returns a copy of this string with all | |
2641 uppercase letters changed to lowercase. | |
2642 All other characters are left unchanged. | |
2643 </p> | |
2644 <% | |
2645 end | |
2646 } | |
1716 | 2647 ["String.regex"] = { |
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2648 title = "String.regex (s)" |
1716 | 2649 content = function() |
2650 %> | |
2651 <p> | |
2652 Returns a <a href="#regex_table">regex</a> table for the pattern <code>s</code>. | |
2653 </p> | |
2654 <% | |
2655 end | |
2656 } | |
1668 | 2657 ["String.regex_quote"] = { |
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2658 title = "String.regex_quote (s)" |
1668 | 2659 content = function() |
2660 %> | |
2661 <p> | |
1816 | 2662 Returns a string which matches the literal string <code>s</code> in a regular expression. This function is simply the Java method <a href="https://docs.oracle.com/javase/8/docs/api/java/util/regex/Pattern.html#quote-java.lang.String-"><code>Pattern.quote</code></a>. |
1668 | 2663 </p> |
2664 <% | |
2665 end | |
2666 } | |
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2667 ["String.repeated"] = { |
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2668 title = "String.repeated (s, n [, sep])" |
1668 | 2669 content = function() |
2670 %> | |
2671 <p> | |
2672 Returns a string that is the concatenation of <code>n</code> copies of | |
2673 the string <code>s</code> separated by the string <code>sep</code>. | |
2674 The default value for <code>sep</code> is the empty string | |
2675 (that is, no separator). | |
2676 Returns the empty string if <code>n</code> is not positive. | |
2677 </p> | |
2678 <% | |
2679 end | |
2680 } | |
1717 | 2681 ["String.replace"] = { |
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2682 title = "String.replace (s, target, replacement)" |
1717 | 2683 content = function() |
2684 %> | |
2685 <p> | |
2686 Returns a string where each substring <code>target</code> in <code>s</code> is replaced by <code>replacement</code>. | |
2687 </p> | |
2688 <% | |
2689 end | |
2690 } | |
1668 | 2691 ["String.reverse"] = { |
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2692 title = "String.reverse (s)" |
1668 | 2693 content = function() |
2694 %> | |
2695 <p> | |
2696 Returns a string that is the string <code>s</code> reversed. | |
2697 </p> | |
2698 <% | |
2699 end | |
2700 } | |
2701 ["String.split"] = { | |
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2702 title = "String.split (s, s2 [, limit])" |
1668 | 2703 content = function() |
2704 %> | |
2705 <p> | |
1721
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2706 Splits <code>s</code> using substring <code>s2</code> and returns the results. If <code>limit</code> is positive, then only returns at most that many results. If <code>limit</code> is zero, then remove trailing empty results. |
1668 | 2707 </p> |
2708 <% | |
2709 end | |
2710 } | |
1716 | 2711 ["String.starts_with"] = { |
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2712 title = "String.starts_with (s, s2)" |
1716 | 2713 content = function() |
2714 %> | |
2715 <p> | |
2716 Returns a boolean indicating whether the <code>s</code> starts with <code>s2</code>. | |
2717 </p> | |
2718 <% | |
2719 end | |
2720 } | |
1668 | 2721 ["String.sub"] = { |
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2722 title = "String.sub (s, i [, j])" |
1668 | 2723 content = function() |
2724 %> | |
2725 <p> | |
2726 Returns the substring of <code>s</code> that | |
2727 starts at <code>i</code> and continues until <code>j</code>; | |
2728 <code>i</code> and <code>j</code> can be negative. | |
2729 If <code>j</code> is absent, then it is assumed to be equal to -1 | |
2730 (which is the same as the string length). | |
2731 In particular, | |
2732 the call <code>string.sub(s,1,j)</code> returns a prefix of <code>s</code> | |
2733 with length <code>j</code>, | |
2734 and <code>string.sub(s, -i)</code> returns a suffix of <code>s</code> | |
2735 with length <code>i</code>. | |
2736 </p> | |
2737 | |
2738 <p> | |
2739 If, after the translation of negative indices, | |
2740 <code>i</code> is less than 1, | |
2741 it is corrected to 1. | |
2742 If <code>j</code> is greater than the string length, | |
2743 it is corrected to that length. | |
2744 If, after these corrections, | |
2745 <code>i</code> is greater than <code>j</code>, | |
2746 the function returns the empty string. | |
2747 </p> | |
2748 <% | |
2749 end | |
2750 } | |
2751 ["String.to_binary"] = { | |
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2752 title = "String.to_binary (s)" |
1668 | 2753 content = function() |
2754 %> | |
2755 <p> | |
1816 | 2756 Converts a string to a binary by calling the Java method <a href="https://docs.oracle.com/javase/8/docs/api/java/lang/String.html#getBytes--"><code>String.getBytes</code></a>. |
1668 | 2757 </p> |
2758 <% | |
2759 end | |
2760 } | |
2761 ["String.to_number"] = { | |
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2762 title = "String.to_number (s [, base])" |
1668 | 2763 content = function() |
2764 %> | |
2765 <p> | |
2766 When called with no <code>base</code>, | |
2767 <code>to_number</code> tries to convert its argument to a number. | |
2768 If the argument is | |
2769 a string convertible to a number, | |
2770 then <code>to_number</code> returns this number; | |
2771 otherwise, it returns <b>nil</b>. | |
2772 The conversion of strings can result in integers or floats. | |
2773 </p> | |
2774 | |
2775 <p> | |
2776 When called with <code>base</code>, | |
2777 then <code>s</code> must be a string to be interpreted as | |
2778 an integer numeral in that base. | |
2779 In bases above 10, the letter '<code>A</code>' (in either upper or lower case) | |
2780 represents 10, '<code>B</code>' represents 11, and so forth, | |
2781 with '<code>Z</code>' representing 35. | |
2782 If the string <code>s</code> is not a valid numeral in the given base, | |
2783 the function returns <b>nil</b>. | |
2784 </p> | |
2785 <% | |
2786 end | |
2787 } | |
2788 ["String.trim"] = { | |
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2789 title = "String.trim (s)" |
1668 | 2790 content = function() |
2791 %> | |
2792 <p> | |
1816 | 2793 Removes the leading and trailing whitespace by calling the Java method <a href="https://docs.oracle.com/javase/8/docs/api/java/lang/String.html#trim--"><code>String.trim</code></a>. |
1668 | 2794 </p> |
2795 <% | |
2796 end | |
2797 } | |
2798 ["String.unicode"] = { | |
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2799 title = "String.unicode (s [, i [, j]])" |
1668 | 2800 content = function() |
2801 %> | |
2802 <p> | |
2803 Returns the internal numerical codes of the characters <code>s[i]</code>, | |
2804 <code>s[i+1]</code>, ..., <code>s[j]</code>. | |
2805 The default value for <code>i</code> is 1; | |
2806 the default value for <code>j</code> is <code>i</code>. | |
2807 These indices are corrected | |
2808 following the same rules of function <a href="#String.sub"><code>String.sub</code></a>. | |
2809 </p> | |
2810 <% | |
2811 end | |
2812 } | |
2813 ["String.upper"] = { | |
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2814 title = "String.upper (s)" |
1668 | 2815 content = function() |
2816 %> | |
2817 <p> | |
2818 Receives a string and returns a copy of this string with all | |
2819 lowercase letters changed to uppercase. | |
2820 All other characters are left unchanged. | |
2821 The definition of what a lowercase letter is depends on the current locale. | |
2822 </p> | |
2823 <% | |
2824 end | |
2825 } | |
2826 } | |
2827 } | |
1716 | 2828 regex_table = { |
2829 title = "Regular Expressions" | |
2830 content = function() | |
2831 %> | |
2832 <p> | |
2833 Regular expressions are handled using a regex table generated by <a href="#String.regex">String.regex</a>. | |
2834 </p> | |
2835 | |
2836 <p> | |
1816 | 2837 Pattern matching is based on the Java <a href="https://docs.oracle.com/javase/8/docs/api/java/util/regex/Pattern.html">Pattern</a> class. |
1716 | 2838 </p> |
2839 <% | |
2840 end | |
2841 subs = { | |
2842 ["regex.find"] = { | |
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2843 title = "regex.find (s [, init])" |
1716 | 2844 content = function() |
2845 %> | |
2846 <p> | |
2847 Looks for the first match of | |
2848 the regex in the string <code>s</code>. | |
2849 If it finds a match, then <code>find</code> returns the indices of <code>s</code> | |
2850 where this occurrence starts and ends; | |
2851 otherwise, it returns <b>nil</b>. | |
2852 A third, optional numerical argument <code>init</code> specifies | |
2853 where to start the search; | |
2854 its default value is 1 and can be negative. | |
2855 </p> | |
2856 | |
2857 <p> | |
2858 If the regex has captures, | |
2859 then in a successful match | |
2860 the captured values are also returned, | |
2861 after the two indices. | |
2862 </p> | |
2863 <% | |
2864 end | |
2865 } | |
2866 ["regex.gmatch"] = { | |
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2867 title = "regex.gmatch (s)" |
1716 | 2868 content = function() |
2869 %> | |
2870 <p> | |
2871 Returns an iterator function that, | |
2872 each time it is called, | |
2873 returns the next captures from the regex | |
2874 over the string <code>s</code>. | |
2875 If the regex specifies no captures, | |
2876 then the whole match is produced in each call. | |
2877 </p> | |
2878 | |
2879 <p> | |
2880 As an example, the following loop | |
2881 will iterate over all the words from string <code>s</code>, | |
2882 printing one per line: | |
2883 </p> | |
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2884 <code block> |
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2885 local r = String.regex[[\w+]] |
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2886 local s = "hello world from Lua" |
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2887 for w in r.gmatch(s) do |
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2888 print(w) |
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2889 end |
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2890 </code> |
1716 | 2891 |
2892 <p> | |
2893 The next example collects all pairs <code>key=value</code> from the | |
2894 given string into a table: | |
2895 </p> | |
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2896 <code block> |
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2897 local t = {} |
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2898 local r = String.regex[[(\w+)=(\w+)]] |
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2899 local s = "from=world, to=Lua" |
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2900 for k, v in r.gmatch(s) do |
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2901 t[k] = v |
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2902 end |
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2903 </code> |
1716 | 2904 |
2905 <p> | |
2906 For this function, a caret '<code>^</code>' at the start of a pattern does not | |
2907 work as an anchor, as this would prevent the iteration. | |
2908 </p> | |
2909 <% | |
2910 end | |
2911 } | |
2912 ["regex.gsub"] = { | |
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2913 title = "regex.gsub (s, repl [, n])" |
1716 | 2914 content = function() |
2915 %> | |
2916 <p> | |
2917 Returns a copy of <code>s</code> | |
2918 in which all (or the first <code>n</code>, if given) | |
2919 occurrences of the regex have been | |
2920 replaced by a replacement string specified by <code>repl</code>, | |
2921 which can be a string, a table, or a function. | |
2922 <code>gsub</code> also returns, as its second value, | |
2923 the total number of matches that occurred. | |
2924 The name <code>gsub</code> comes from <em>Global SUBstitution</em>. | |
2925 </p> | |
2926 | |
2927 <p> | |
2928 If <code>repl</code> is a string, then its value is used for replacement. | |
2929 The character <code>\</code> works as an escape character. | |
2930 Any sequence in <code>repl</code> of the form <code>$<em>d</em></code>, | |
2931 with <em>d</em> between 1 and 9, | |
2932 stands for the value of the <em>d</em>-th captured substring. | |
2933 The sequence <code>$0</code> stands for the whole match. | |
2934 </p> | |
2935 | |
2936 <p> | |
2937 If <code>repl</code> is a table, then the table is queried for every match, | |
2938 using the first capture as the key. | |
2939 </p> | |
2940 | |
2941 <p> | |
2942 If <code>repl</code> is a function, then this function is called every time a | |
2943 match occurs, with all captured substrings passed as arguments, | |
2944 in order. | |
2945 </p> | |
2946 | |
2947 <p> | |
2948 In any case, | |
2949 if the regex specifies no captures, | |
2950 then it behaves as if the whole regex was inside a capture. | |
2951 </p> | |
2952 | |
2953 <p> | |
2954 If the value returned by the table query or by the function call | |
2955 is not <b>nil</b>, | |
2956 then it is used as the replacement string; | |
2957 otherwise, if it is <b>nil</b>, | |
2958 then there is no replacement | |
2959 (that is, the original match is kept in the string). | |
2960 </p> | |
2961 | |
2962 <p> | |
2963 Here are some examples: | |
2964 </p> | |
2965 | |
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2966 <code block> |
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2967 local r = String.regex[[(\w+)]] |
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2968 local x = r.gsub("hello world", "$1 $1") |
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2969 --> x="hello hello world world" |
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2970 |
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2971 local r = String.regex[[(\w+)]] |
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2972 local x = r.gsub("hello world", "$0 $0", 1) |
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2973 --> x="hello hello world" |
1716 | 2974 |
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2975 local r = String.regex[[(\w+)\s*(\w+)]] |
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2976 local x = r.gsub("hello world from Luan", "$2 $1") |
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2977 --> x="world hello Luan from" |
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2978 |
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2979 local r = String.regex[[\$(.*?)\$]] |
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2980 local x = r.gsub("4+5 = $return 4+5$", function(s) |
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2981 return load(s)() |
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2982 end) |
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2983 --> x="4+5 = 9" |
1716 | 2984 |
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2985 local r = String.regex[[\$(\w+)]] |
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2986 local t = {name="lua", version="5.3"} |
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2987 local x = r.gsub("$name-$version.tar.gz", t) |
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2988 --> x="lua-5.3.tar.gz" |
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2989 </code> |
1716 | 2990 <% |
2991 end | |
2992 } | |
2993 ["regex.match"] = { | |
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2994 title = "regex.match (s [, init])" |
1716 | 2995 content = function() |
2996 %> | |
2997 <p> | |
2998 Looks for the first <em>match</em> of | |
2999 the regex in the string <code>s</code>. | |
3000 If it finds one, then <code>match</code> returns | |
3001 the captures from the regex; | |
3002 otherwise it returns <b>nil</b>. | |
3003 If the regex specifies no captures, | |
3004 then the whole match is returned. | |
3005 A third, optional numerical argument <code>init</code> specifies | |
3006 where to start the search; | |
3007 its default value is 1 and can be negative. | |
3008 </p> | |
3009 <% | |
3010 end | |
3011 } | |
3012 ["regex.matches"] = { | |
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3013 title = "regex.matches (s)" |
1716 | 3014 content = function() |
3015 %> | |
3016 <p> | |
3017 Returns a boolean indicating whether the regex can be found in string <code>s</code>. | |
3018 This function is equivalent to | |
3019 </p> | |
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3020 <code block> |
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3021 return regex.match(s) ~= nil |
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3022 </code> |
1716 | 3023 <% |
3024 end | |
3025 } | |
1719 | 3026 ["regex.set"] = { |
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3027 title = "regex.set (pattern)" |
1719 | 3028 content = function() |
3029 %> | |
3030 <p> | |
3031 Changes the regex pattern to <code>pattern</code>. | |
3032 </p> | |
3033 <% | |
3034 end | |
3035 } | |
3036 ["regex.split"] = { | |
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3037 title = "regex.split (s [, limit])" |
1719 | 3038 content = function() |
3039 %> | |
3040 <p> | |
3041 Splits <code>s</code> using the regex and returns the results. If <code>limit</code> is positive, then only returns at most that many results. If <code>limit</code> is zero, then remove trailing empty results. | |
3042 </p> | |
3043 <% | |
3044 end | |
3045 } | |
1716 | 3046 } |
3047 } | |
1668 | 3048 binary_lib = { |
3049 title = "Binary Manipulation" | |
3050 content = function() | |
3051 %> | |
3052 <p> | |
3053 Include this library by: | |
3054 </p> | |
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3055 <code block> |
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3056 local Binary = require "luan:Binary.luan" |
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3057 </code> |
1668 | 3058 <% |
3059 end | |
3060 subs = { | |
1816 | 3061 ["Binary.base64_decode"] = { |
3062 title = "Binary.base64_decode (s)" | |
3063 content = function() | |
3064 %> | |
3065 <p>Same as Java's <a href="https://docs.oracle.com/javase/8/docs/api/java/util/Base64.Decoder.html#decode-java.lang.String-">Base64.Decoder.decode</a>.</p> | |
3066 <% | |
3067 end | |
3068 } | |
3069 ["Binary.base64_encode"] = { | |
3070 title = "Binary.base64_encode (b)" | |
3071 content = function() | |
3072 %> | |
3073 <p>Same as Java's <a href="https://docs.oracle.com/javase/8/docs/api/java/util/Base64.Encoder.html#encodeToString-byte:A-">Base64.Encoder.encodeToString</a>.</p> | |
3074 <% | |
3075 end | |
3076 } | |
1668 | 3077 ["Binary.binary"] = { |
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3078 title = "Binary.binary (···)" |
1668 | 3079 content = function() |
3080 %> | |
3081 <p> | |
3082 Receives zero or more bytes (as integers). | |
3083 Returns a binary with length equal to the number of arguments, | |
3084 in which each byte has the internal numerical code equal | |
3085 to its corresponding argument. | |
3086 </p> | |
3087 <% | |
3088 end | |
3089 } | |
3090 ["Binary.byte"] = { | |
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3091 title = "Binary.byte (b [, i [, j]])" |
1668 | 3092 content = function() |
3093 %> | |
3094 <p> | |
3095 Returns the internal numerical codes of the bytes <code>b[i]</code>, | |
3096 <code>b[i+1]</code>, ..., <code>b[j]</code>. | |
3097 The default value for <code>i</code> is 1; | |
3098 the default value for <code>j</code> is <code>i</code>. | |
3099 These indices are corrected | |
3100 following the same rules of function <a href="#String.sub"><code>String.sub</code></a>. | |
3101 </p> | |
3102 <% | |
3103 end | |
3104 } | |
1816 | 3105 ["Binary.digest_message"] = { |
3106 title = "Binary.digest_message (algorithm, b)" | |
3107 content = function() | |
3108 %> | |
3109 <p>Implemented in Java as:</p> | |
3110 | |
3111 <code block> | |
3112 return <a href="https://docs.oracle.com/javase/8/docs/api/java/security/MessageDigest.html">MessageDigest</a>.<a href="https://docs.oracle.com/javase/8/docs/api/java/security/MessageDigest.html#getInstance-java.lang.String-">getInstance</a>(algorithm).<a href="https://docs.oracle.com/javase/8/docs/api/java/security/MessageDigest.html#digest-byte:A-">digest</a>(b); | |
3113 </code> | |
3114 <% | |
3115 end | |
3116 } | |
3117 ["Binary.to_hex"] = { | |
3118 title = "Binary.to_hex (b)" | |
3119 content = function() | |
3120 %> | |
3121 <p>Converts a binary to a hex string.</p> | |
3122 <% | |
3123 end | |
3124 } | |
1668 | 3125 ["Binary.to_string"] = { |
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3126 title = "Binary.to_string (b [,charset])" |
1668 | 3127 content = function() |
3128 %> | |
3129 <p> | |
1816 | 3130 If <code>charset</code> is not nil then converts the binary <code>b</code> to a string using the Java <a href="https://docs.oracle.com/javase/8/docs/api/java/lang/String.html#String-byte:A-java.lang.String-">String constructor</a>, else makes each byte a char. |
1668 | 3131 </p> |
3132 <% | |
3133 end | |
3134 } | |
3135 } | |
3136 } | |
3137 table_lib = { | |
3138 title = "Table Manipulation" | |
3139 content = function() | |
3140 %> | |
3141 <p> | |
3142 Include this library by: | |
3143 </p> | |
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3144 <code block> |
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3145 local Table = require "luan:Table.luan" |
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3146 </code> |
1668 | 3147 |
3148 <p> | |
3149 This library provides generic functions for table manipulation. | |
3150 It provides all its functions inside the table <code>Table</code>. | |
3151 </p> | |
3152 <% | |
3153 end | |
3154 subs = { | |
1817 | 3155 ["Table.case_insensitive"] = { |
3156 title = "Table.case_insensitive ([tbl])" | |
3157 content = function() | |
3158 %> | |
3159 <p>Returns a table with case-insensitive string keys. Copies <code>tbl</code> or is empty.</p> | |
3160 <% | |
3161 end | |
3162 } | |
1668 | 3163 ["Table.clear"] = { |
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3164 title = "Table.clear (tbl)" |
1668 | 3165 content = function() |
3166 %> | |
3167 <p> | |
3168 Clears the table. | |
3169 </p> | |
3170 <% | |
3171 end | |
3172 } | |
3173 ["Table.concat"] = { | |
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3174 title = "Table.concat (list [, sep [, i [, j]]])" |
1668 | 3175 content = function() |
3176 %> | |
3177 <p> | |
3178 Given a list, | |
3179 returns the string <code>list[i]..sep..list[i+1] ··· sep..list[j]</code>. | |
3180 The default value for <code>sep</code> is the empty string, | |
3181 the default for <code>i</code> is 1, | |
3182 and the default for <code>j</code> is <code>#list</code>. | |
3183 If <code>i</code> is greater than <code>j</code>, returns the empty string. | |
3184 </p> | |
3185 <% | |
3186 end | |
3187 } | |
3188 ["Table.copy"] = { | |
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3189 title = "Table.copy (tbl [, i [, j]])" |
1668 | 3190 content = function() |
3191 %> | |
3192 <p> | |
3193 If <code>i</code> is <code>nil</code>, returns a shallow copy of <code>tbl</code>. | |
3194 Otherwise returns a new table which is a list of the elements <code>tbl[i] ··· tbl[j]</code>. | |
3195 By default, <code>j</code> is <code>#tbl</code>. | |
3196 </p> | |
3197 <% | |
3198 end | |
3199 } | |
3200 ["Table.insert"] = { | |
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3201 title = "Table.insert (list, pos, value)" |
1668 | 3202 content = function() |
3203 %> | |
3204 <p> | |
3205 Inserts element <code>value</code> at position <code>pos</code> in <code>list</code>, | |
3206 shifting up the elements | |
3207 <code>list[pos], list[pos+1], ···, list[#list]</code>. | |
3208 </p> | |
3209 <% | |
3210 end | |
3211 } | |
3212 ["Table.is_empty"] = { | |
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3213 title = "Table.is_empty (tbl)" |
1668 | 3214 content = function() |
3215 %> | |
3216 <% | |
3217 end | |
3218 } | |
1704 | 3219 ["Table.is_list"] = { |
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3220 title = "Table.is_list (tbl)" |
1704 | 3221 content = function() |
3222 %> | |
3223 <% | |
3224 end | |
3225 } | |
1817 | 3226 ["Table.java_to_table_deep"] = { |
3227 title = "Table.java_to_table_deep (obj [, java_to_table_shallow])" | |
3228 content = function() | |
3229 %> | |
3230 <p>Recursively applies <code>java_to_table_shallow</code> to convert a Java object to nested tables. <code>java_to_table_shallow</code> defaults to <a href="#Table.java_to_table_shallow">Table.java_to_table_shallow</a>.</p> | |
3231 <% | |
3232 end | |
3233 } | |
3234 ["Table.java_to_table_shallow"] = { | |
3235 title = "Table.java_to_table_shallow (obj)" | |
3236 content = function() | |
3237 %> | |
3238 <p>Converts a Java object to a table. Works for collection types List, Map, Set, and Java arrays.</p> | |
3239 <% | |
3240 end | |
3241 } | |
1668 | 3242 ["Table.pack"] = { |
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3243 title = "Table.pack (···)" |
1668 | 3244 content = function() |
3245 %> | |
3246 <p> | |
3247 Returns a new table with all parameters stored into keys 1, 2, etc. | |
3248 and with a field "<code>n</code>" with the total number of parameters. | |
3249 Note that the resulting table may not be a sequence. | |
3250 </p> | |
3251 <% | |
3252 end | |
3253 } | |
3254 ["Table.remove"] = { | |
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3255 title = "Table.remove (list, pos)" |
1668 | 3256 content = function() |
3257 %> | |
3258 <p> | |
3259 Removes from <code>list</code> the element at position <code>pos</code>, | |
3260 returning the value of the removed element. | |
3261 When <code>pos</code> is an integer between 1 and <code>#list</code>, | |
3262 it shifts down the elements | |
3263 <code>list[pos+1], list[pos+2], ···, list[#list]</code> | |
3264 and erases element <code>list[#list]</code>; | |
3265 The index <code>pos</code> can also be 0 when <code>#list</code> is 0, | |
3266 or <code>#list + 1</code>; | |
3267 in those cases, the function erases the element <code>list[pos]</code>. | |
3268 </p> | |
3269 <% | |
3270 end | |
3271 } | |
3272 ["Table.size"] = { | |
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3273 title = "Table.size (tbl)" |
1668 | 3274 content = function() |
3275 %> | |
3276 <% | |
3277 end | |
3278 } | |
3279 ["Table.sort"] = { | |
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3280 title = "Table.sort (list [, comp])" |
1668 | 3281 content = function() |
3282 %> | |
3283 <p> | |
3284 Sorts list elements in a given order, <em>in-place</em>, | |
3285 from <code>list[1]</code> to <code>list[#list]</code>. | |
3286 If <code>comp</code> is given, | |
3287 then it must be a function that receives two list elements | |
3288 and returns true when the first element must come | |
3289 before the second in the final order | |
3290 (so that <code>not comp(list[i+1],list[i])</code> will be true after the sort). | |
3291 If <code>comp</code> is not given, | |
3292 then the standard Lua operator <code><</code> is used instead. | |
3293 </p> | |
3294 | |
3295 <p> | |
3296 The sort algorithm is not stable; | |
3297 that is, elements considered equal by the given order | |
3298 may have their relative positions changed by the sort. | |
3299 </p> | |
3300 <% | |
3301 end | |
3302 } | |
3303 ["Table.unpack"] = { | |
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3304 title = "Table.unpack (list [, i [, j]])" |
1668 | 3305 content = function() |
3306 %> | |
3307 <p> | |
3308 Returns the elements from the given list. | |
3309 This function is equivalent to | |
3310 </p> | |
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3311 <code block> |
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3312 return list[i], list[i+1], ···, list[j] |
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3313 </code> |
1668 | 3314 |
3315 <p> | |
3316 By default, <code>i</code> is 1 and <code>j</code> is <code>list.n or #list</code>. | |
3317 </p> | |
3318 <% | |
3319 end | |
3320 } | |
3321 } | |
3322 } | |
3323 number_lib = { | |
3324 title = "Number Manipulation" | |
3325 content = function() | |
3326 %> | |
3327 <p> | |
3328 Include this library by: | |
3329 </p> | |
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3330 <code block> |
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3331 local Number = require "luan:Number.luan" |
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3332 </code> |
1668 | 3333 <% |
3334 end | |
3335 subs = { | |
3336 ["Number.double"] = { | |
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3337 title = "Number.double (x)" |
1668 | 3338 content = function() |
3339 %> | |
3340 <p> | |
3341 Returns <code>x</code> as a double. | |
3342 </p> | |
3343 <% | |
3344 end | |
3345 } | |
3346 ["Number.float"] = { | |
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3347 title = "Number.float (x)" |
1668 | 3348 content = function() |
3349 %> | |
3350 <p> | |
3351 Returns <code>x</code> as a float. | |
3352 </p> | |
3353 <% | |
3354 end | |
3355 } | |
3356 ["Number.integer"] = { | |
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3357 title = "Number.integer (x)" |
1668 | 3358 content = function() |
3359 %> | |
3360 <p> | |
3361 If the value <code>x</code> is convertible to an integer, | |
3362 returns that integer. | |
3363 Otherwise throws an error. | |
3364 </p> | |
3365 <% | |
3366 end | |
3367 } | |
3368 ["Number.long"] = { | |
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3369 title = "Number.long (x)" |
1668 | 3370 content = function() |
3371 %> | |
3372 <p> | |
3373 If the value <code>x</code> is convertible to an long, | |
3374 returns that long. | |
3375 Otherwise throws an error. | |
3376 </p> | |
3377 <% | |
3378 end | |
3379 } | |
3380 ["Number.long_to_string"] = { | |
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3381 title = "Number.long_to_string (i, radix)" |
1668 | 3382 content = function() |
3383 %> | |
3384 <p> | |
1816 | 3385 Converts long value <code>i</code> to a string by calling <code><a href="https://docs.oracle.com/javase/8/docs/api/java/lang/Long.html#toString-long-int-">Long.toString</a></code>. |
1668 | 3386 </p> |
3387 <% | |
3388 end | |
3389 } | |
3390 ["Number.type"] = { | |
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3391 title = "Number.type (x)" |
1668 | 3392 content = function() |
3393 %> | |
3394 <p> | |
3395 Returns a string for the numeric type of <code>x</code>. Possible return values include "<code>integer</code>", "<code>long</code>", "<code>double</code>", and "<code>float</code>". | |
3396 </p> | |
3397 <% | |
3398 end | |
3399 } | |
3400 } | |
3401 } | |
1669 | 3402 math_lib = { |
3403 title = "Mathematical Functions" | |
3404 content = function() | |
3405 %> | |
3406 <p> | |
3407 Include this library by: | |
3408 </p> | |
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3409 <code block> |
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3410 local Math = require "luan:Math.luan" |
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3411 </code> |
1669 | 3412 |
3413 <p> | |
3414 This library provides basic mathematical functions. | |
3415 It provides all its functions and constants inside the table <code>Math</code>. | |
3416 </p> | |
3417 <% | |
3418 end | |
3419 subs = { | |
3420 ["Math.abs"] = { | |
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3421 title = "Math.abs (x)" |
1669 | 3422 content = function() |
3423 %> | |
3424 <p> | |
3425 Returns the absolute value of <code>x</code>. | |
3426 </p> | |
3427 <% | |
3428 end | |
3429 } | |
3430 ["Math.acos"] = { | |
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3431 title = "Math.acos (x)" |
1669 | 3432 content = function() |
3433 %> | |
3434 <p> | |
3435 Returns the arc cosine of <code>x</code> (in radians). | |
3436 </p> | |
3437 <% | |
3438 end | |
3439 } | |
3440 ["Math.asin"] = { | |
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3441 title = "Math.asin (x)" |
1669 | 3442 content = function() |
3443 %> | |
3444 <p> | |
3445 Returns the arc sine of <code>x</code> (in radians). | |
3446 </p> | |
3447 <% | |
3448 end | |
3449 } | |
3450 ["Math.atan"] = { | |
1818 | 3451 title = "Math.atan (a)" |
3452 content = function() | |
3453 %> | |
3454 <p> | |
3455 Returns the arc tangent of a value; the returned angle is in the range -pi/2 through pi/2.</p> | |
3456 <% | |
3457 end | |
3458 } | |
3459 ["Math.atan2"] = { | |
3460 title = "Math.atan2 (y, x)" | |
1669 | 3461 content = function() |
3462 %> | |
3463 <p> | |
3464 Returns the arc tangent of <code>y/x</code> (in radians), | |
3465 but uses the signs of both parameters to find the | |
3466 quadrant of the result. | |
3467 (It also handles correctly the case of <code>x</code> being zero.) | |
3468 </p> | |
3469 <% | |
3470 end | |
3471 } | |
3472 ["Math.ceil"] = { | |
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3473 title = "Math.ceil (x)" |
1669 | 3474 content = function() |
3475 %> | |
3476 <p> | |
3477 Returns the smallest integral value larger than or equal to <code>x</code>. | |
3478 </p> | |
3479 <% | |
3480 end | |
3481 } | |
3482 ["Math.cos"] = { | |
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3483 title = "Math.cos (x)" |
1669 | 3484 content = function() |
3485 %> | |
3486 <p> | |
3487 Returns the cosine of <code>x</code> (assumed to be in radians). | |
3488 </p> | |
3489 <% | |
3490 end | |
3491 } | |
3492 ["Math.deg"] = { | |
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3493 title = "Math.deg (x)" |
1669 | 3494 content = function() |
3495 %> | |
3496 <p> | |
3497 Converts the angle <code>x</code> from radians to degrees. | |
3498 </p> | |
3499 <% | |
3500 end | |
3501 } | |
3502 ["Math.exp"] = { | |
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3503 title = "Math.exp (x)" |
1669 | 3504 content = function() |
3505 %> | |
3506 <p> | |
3507 Returns the value <em>e<sup>x</sup></em> | |
3508 (where <code>e</code> is the base of natural logarithms). | |
3509 </p> | |
3510 <% | |
3511 end | |
3512 } | |
3513 ["Math.floor"] = { | |
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3514 title = "Math.floor (x)" |
1669 | 3515 content = function() |
3516 %> | |
3517 <p> | |
3518 Returns the largest integral value smaller than or equal to <code>x</code>. | |
3519 </p> | |
3520 <% | |
3521 end | |
3522 } | |
3523 ["Math.fmod"] = { | |
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3524 title = "Math.fmod (x, y)" |
1669 | 3525 content = function() |
3526 %> | |
3527 <p> | |
3528 Returns the remainder of the division of <code>x</code> by <code>y</code> | |
3529 that rounds the quotient towards zero. | |
3530 </p> | |
3531 <% | |
3532 end | |
3533 } | |
3534 ["Math.huge"] = { | |
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3535 title = "Math.huge" |
1669 | 3536 content = function() |
3537 %> | |
3538 <p> | |
3539 A value larger than any other numerical value. | |
3540 </p> | |
3541 <% | |
3542 end | |
3543 } | |
3544 ["Math.log"] = { | |
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3545 title = "Math.log (x [, base])" |
1669 | 3546 content = function() |
3547 %> | |
3548 <p> | |
3549 Returns the logarithm of <code>x</code> in the given base. | |
3550 The default for <code>base</code> is <em>e</em> | |
3551 (so that the function returns the natural logarithm of <code>x</code>). | |
3552 </p> | |
3553 <% | |
3554 end | |
3555 } | |
3556 ["Math.max"] = { | |
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3557 title = "Math.max (x, ···)" |
1669 | 3558 content = function() |
3559 %> | |
3560 <p> | |
3561 Returns the argument with the maximum value, | |
3562 according to the Lua operator <code><</code>. | |
3563 </p> | |
3564 <% | |
3565 end | |
3566 } | |
3567 ["Math.max_integer"] = { | |
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3568 title = "Math.max_integer" |
1669 | 3569 content = function() |
3570 %> | |
3571 <p> | |
3572 An integer with the maximum value for an integer. | |
3573 </p> | |
3574 <% | |
3575 end | |
3576 } | |
3577 ["Math.min"] = { | |
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3578 title = "Math.min (x, ···)" |
1669 | 3579 content = function() |
3580 %> | |
3581 <p> | |
3582 Returns the argument with the minimum value, | |
3583 according to the Lua operator <code><</code>. | |
3584 </p> | |
3585 <% | |
3586 end | |
3587 } | |
3588 ["Math.min_integer"] = { | |
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3589 title = "Math.min_integer" |
1669 | 3590 content = function() |
3591 %> | |
3592 <p> | |
3593 An integer with the minimum value for an integer. | |
3594 </p> | |
3595 <% | |
3596 end | |
3597 } | |
3598 ["Math.modf"] = { | |
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3599 title = "Math.modf (x)" |
1669 | 3600 content = function() |
3601 %> | |
3602 <p> | |
3603 Returns the integral part of <code>x</code> and the fractional part of <code>x</code>. | |
3604 </p> | |
3605 <% | |
3606 end | |
3607 } | |
3608 ["Math.pi"] = { | |
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3609 title = "Math.pi" |
1669 | 3610 content = function() |
3611 %> | |
3612 <p> | |
3613 The value of <em>π</em>. | |
3614 </p> | |
3615 <% | |
3616 end | |
3617 } | |
3618 ["Math.rad"] = { | |
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3619 title = "Math.rad (x)" |
1669 | 3620 content = function() |
3621 %> | |
3622 <p> | |
3623 Converts the angle <code>x</code> from degrees to radians. | |
3624 </p> | |
3625 <% | |
3626 end | |
3627 } | |
3628 ["Math.random"] = { | |
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3629 title = "Math.random ([m [, n])" |
1669 | 3630 content = function() |
3631 %> | |
3632 <p> | |
3633 When called without arguments, | |
3634 returns a pseudo-random float with uniform distribution | |
3635 in the range <em>[0,1)</em>. | |
3636 When called with two integers <code>m</code> and <code>n</code>, | |
3637 <code>Math.random</code> returns a pseudo-random integer | |
3638 with uniform distribution in the range <em>[m, n]</em>. | |
3639 (The value <em>m-n</em> cannot be negative and must fit in a Luan integer.) | |
3640 The call <code>Math.random(n)</code> is equivalent to <code>Math.random(1,n)</code>. | |
3641 </p> | |
3642 | |
3643 <p> | |
3644 This function is an interface to the underling | |
3645 pseudo-random generator function provided by Java. | |
3646 No guarantees can be given for its statistical properties. | |
3647 </p> | |
3648 <% | |
3649 end | |
3650 } | |
3651 ["Math.sin"] = { | |
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3652 title = "Math.sin (x)" |
1669 | 3653 content = function() |
3654 %> | |
3655 <p> | |
3656 Returns the sine of <code>x</code> (assumed to be in radians). | |
3657 </p> | |
3658 <% | |
3659 end | |
3660 } | |
3661 ["Math.sqrt"] = { | |
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3662 title = "Math.sqrt (x)" |
1669 | 3663 content = function() |
3664 %> | |
3665 <p> | |
3666 Returns the square root of <code>x</code>. | |
3667 (You can also use the expression <code>x^0.5</code> to compute this value.) | |
3668 </p> | |
3669 <% | |
3670 end | |
3671 } | |
3672 ["Math.tan"] = { | |
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3673 title = "Math.tan (x)" |
1669 | 3674 content = function() |
3675 %> | |
3676 <p> | |
3677 Returns the tangent of <code>x</code> (assumed to be in radians). | |
3678 </p> | |
3679 <% | |
3680 end | |
3681 } | |
3682 } | |
3683 } | |
1656 | 3684 } |
3685 } | |
3686 } | |
3687 | |
3688 | |
3689 return function() | |
1929 | 3690 local lang = get_lang() |
3691 local html = ` | |
1656 | 3692 %> |
3693 <!doctype html> | |
1929 | 3694 <html lang="<%=lang%>"> |
1656 | 3695 <head> |
3696 <% head() %> | |
3697 <title>Luan Reference Manual</title> | |
3698 <style> | |
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3699 p[list] { |
1656 | 3700 font-family: monospace; |
3701 margin-left: 40px; | |
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3702 } |
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3703 p[list] span { |
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3704 display: inline-block; |
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3705 } |
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3706 p[list=keywords] { |
1656 | 3707 max-width: 700px; |
3708 } | |
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3709 p[list=keywords] span { |
1656 | 3710 width: 100px; |
3711 } | |
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3712 p[list=tokens] { |
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3713 max-width: 400px; |
1716 | 3714 } |
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3715 p[list=tokens] span { |
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3716 width: 50px; |
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3717 } |
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3718 li[c_libs] li li > a { |
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3719 font-family: monospace; |
1716 | 3720 } |
1656 | 3721 </style> |
3722 </head> | |
3723 <body> | |
3724 <% docs_header() %> | |
3725 <div content> | |
3726 <h1><a href="manual.html">Luan Reference Manual</a></h1> | |
3727 <p small> | |
3728 Original copyright © 2015 Lua.org, PUC-Rio. | |
3729 Freely available under the terms of the | |
1827 | 3730 <a href="https://www.lua.org/license.html">Lua license</a>. |
1656 | 3731 Modified for Luan. |
3732 </p> | |
3733 <hr> | |
3734 <h2>Contents</h2> | |
3735 <div toc> | |
3736 <% show_toc(content) %> | |
3737 </div> | |
3738 <hr> | |
1929 | 3739 <div placeholder></div> |
1656 | 3740 </div> |
3741 </body> | |
3742 </html> | |
3743 <% | |
1929 | 3744 ` |
3745 if lang == "en" then | |
3746 html = replace( html, "<div placeholder></div>", `show_content(content,2)` ) | |
3747 else | |
3748 local language = languages[lang] or error(lang) | |
3749 html = translate_html(html,language) | |
3750 local parts = {} | |
3751 for id, info in pairs(content) do | |
3752 local part = `show_content_info(id,info,2)` | |
3753 part = translate_html(part,language) | |
3754 parts[#parts+1] = part | |
3755 end | |
3756 html = replace( html, "<div placeholder></div>", concat(parts) ) | |
3757 set_translated() | |
3758 end | |
3759 text_writer().write(html) | |
1656 | 3760 end |