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author Franklin Schmidt <fschmidt@gmail.com>
date Sun, 10 May 2015 20:44:55 -0600
parents 00646edc9d92
children cd22e4694ea3
comparison
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474:00646edc9d92 475:7ac0891718eb
2032 end 2032 end
2033 </pre></tt></p> 2033 </pre></tt></p>
2034 2034
2035 2035
2036 2036
2037 2037 <h4 margin-top="1em"><a name="Luan.pairs"><tt>Luan.pairs (t)</tt></a></h4>
2038 <p> 2038
2039 <hr><h3><a name="pdf-pairs"><code>pairs (t)</code></a></h3> 2039 <p>
2040 2040 If <tt>t</tt> has a metamethod <tt>__pairs</tt>,
2041 2041 calls it with <tt>t</tt> as argument and returns the
2042 <p> 2042 result from the call.
2043 If <code>t</code> has a metamethod <code>__pairs</code>,
2044 calls it with <code>t</code> as argument and returns the first three
2045 results from the call.
2046 2043
2047 2044
2048 <p> 2045 <p>
2049 Otherwise, 2046 Otherwise,
2050 returns three values: the <a href="#pdf-next"><code>next</code></a> function, the table <code>t</code>, and <b>nil</b>, 2047 returns a function
2051 so that the construction 2048 so that the construction
2052 2049
2053 <pre> 2050 <p><tt><pre>
2054 for k,v in pairs(t) do <em>body</em> end 2051 for k,v in pairs(t) do <i>body</i> end
2055 </pre><p> 2052 </pre></tt></p>
2056 will iterate over all key&ndash;value pairs of table <code>t</code>. 2053
2057 2054 <p>
2058 2055 will iterate over all key&ndash;value pairs of table <tt>t</tt>.
2059 <p> 2056
2060 See function <a href="#pdf-next"><code>next</code></a> for the caveats of modifying 2057
2061 the table during its traversal. 2058
2062 2059 <h4 margin-top="1em"><a name="Luan.pcall"><tt>Luan.pcall (f [, arg1, &middot;&middot;&middot;])</tt></a></h4>
2063 2060
2064 2061 <p>
2065 2062 Calls function <tt>f</tt> with
2066 <p> 2063 the given arguments in <i>protected mode</i>.
2067 <hr><h3><a name="pdf-pcall"><code>pcall (f [, arg1, &middot;&middot;&middot;])</code></a></h3> 2064 This means that any error inside&nbsp;<tt>f</tt> is not propagated;
2068 2065 instead, <tt>pcall</tt> catches the error
2069
2070 <p>
2071 Calls function <code>f</code> with
2072 the given arguments in <em>protected mode</em>.
2073 This means that any error inside&nbsp;<code>f</code> is not propagated;
2074 instead, <code>pcall</code> catches the error
2075 and returns a status code. 2066 and returns a status code.
2076 Its first result is the status code (a boolean), 2067 Its first result is the status code (a boolean),
2077 which is true if the call succeeds without errors. 2068 which is true if the call succeeds without errors.
2078 In such case, <code>pcall</code> also returns all results from the call, 2069 In such case, <tt>pcall</tt> also returns all results from the call,
2079 after this first result. 2070 after this first result.
2080 In case of any error, <code>pcall</code> returns <b>false</b> plus the error message. 2071 In case of any error, <tt>pcall</tt> returns <b>false</b> plus the error.
2081 2072
2082 2073
2083 2074
2084 2075
2085 <p> 2076 <p>
2094 use <a href="#pdf-string.format"><code>string.format</code></a> and <a href="#pdf-io.write"><code>io.write</code></a>. 2085 use <a href="#pdf-string.format"><code>string.format</code></a> and <a href="#pdf-io.write"><code>io.write</code></a>.
2095 2086
2096 2087
2097 2088
2098 2089
2099 <p> 2090 <h4 margin-top="1em"><a name="Luan.raw_equal"><tt>Luan.raw_equal (v1, v2)</tt></a></h4>
2100 <hr><h3><a name="pdf-rawequal"><code>rawequal (v1, v2)</code></a></h3> 2091
2101 Checks whether <code>v1</code> is equal to <code>v2</code>, 2092 <p>
2093 Checks whether <tt>v1</tt> is equal to <tt>v2</tt>,
2102 without invoking any metamethod. 2094 without invoking any metamethod.
2103 Returns a boolean. 2095 Returns a boolean.
2104 2096
2105 2097
2106 2098
2107 2099 <h4 margin-top="1em"><a name="Luan.raw_get"><tt>Luan.raw_get (table, index)</tt></a></h4>
2108 <p> 2100
2109 <hr><h3><a name="pdf-rawget"><code>rawget (table, index)</code></a></h3> 2101 <p>
2110 Gets the real value of <code>table[index]</code>, 2102 Gets the real value of <tt>table[index]</tt>,
2111 without invoking any metamethod. 2103 without invoking any metamethod.
2112 <code>table</code> must be a table; 2104 <tt>table</tt> must be a table;
2113 <code>index</code> may be any value. 2105 <tt>index</tt> may be any value.
2114 2106
2115 2107
2116 2108
2117 2109 <h4 margin-top="1em"><a name="Luan.raw_len"><tt>Luan.raw_len (v)</tt></a></h4>
2118 <p> 2110
2119 <hr><h3><a name="pdf-rawlen"><code>rawlen (v)</code></a></h3> 2111 <p>
2120 Returns the length of the object <code>v</code>, 2112 Returns the length of the object <tt>v</tt>,
2121 which must be a table or a string, 2113 which must be a table or a string,
2122 without invoking any metamethod. 2114 without invoking any metamethod.
2123 Returns an integer. 2115 Returns an integer.
2124 2116
2125 2117
2126 2118
2127 2119 <h4 margin-top="1em"><a name="Luan.raw_set"><tt>Luan.raw_set (table, index, value)</tt></a></h4>
2128 <p> 2120
2129 <hr><h3><a name="pdf-rawset"><code>rawset (table, index, value)</code></a></h3> 2121 <p>
2130 Sets the real value of <code>table[index]</code> to <code>value</code>, 2122 Sets the real value of <tt>table[index]</tt> to <tt>value</tt>,
2131 without invoking any metamethod. 2123 without invoking any metamethod.
2132 <code>table</code> must be a table, 2124 <tt>table</tt> must be a table,
2133 <code>index</code> any value different from <b>nil</b> and NaN, 2125 <tt>index</tt> any value different from <b>nil</b>,
2134 and <code>value</code> any Lua value. 2126 and <tt>value</tt> any Lua value.
2135 2127
2136 2128
2137 <p> 2129 <p>
2138 This function returns <code>table</code>. 2130 This function returns <tt>table</tt>.
2139 2131
2140 2132
2141 2133
2142 2134
2143 <p> 2135 <p>
2152 and <code>select</code> returns the total number of extra arguments it received. 2144 and <code>select</code> returns the total number of extra arguments it received.
2153 2145
2154 2146
2155 2147
2156 2148
2157 <p> 2149 <h4 margin-top="1em"><a name="Luan.set_metatable"><tt>Luan.set_metatable (table, metatable)</tt></a></h4>
2158 <hr><h3><a name="pdf-setmetatable"><code>setmetatable (table, metatable)</code></a></h3>
2159
2160 2150
2161 <p> 2151 <p>
2162 Sets the metatable for the given table. 2152 Sets the metatable for the given table.
2163 (You cannot change the metatable of other types from Lua, only from&nbsp;C.) 2153 If <tt>metatable</tt> is <b>nil</b>,
2164 If <code>metatable</code> is <b>nil</b>,
2165 removes the metatable of the given table. 2154 removes the metatable of the given table.
2166 If the original metatable has a <code>"__metatable"</code> field, 2155 If the original metatable has a <tt>"__metatable"</tt> field,
2167 raises an error. 2156 raises an error.
2168 2157
2169 2158
2170 <p> 2159 <p>
2171 This function returns <code>table</code>. 2160 This function returns <tt>table</tt>.
2172 2161
2173 2162
2174 2163
2175 2164
2176 <p> 2165 <p>
2204 the function returns <b>nil</b>. 2193 the function returns <b>nil</b>.
2205 2194
2206 2195
2207 2196
2208 2197
2209 <p> 2198 <h4 margin-top="1em"><a name="Luan.to_string"><tt>Luan.to_string (v)</tt></a></h4>
2210 <hr><h3><a name="pdf-tostring"><code>tostring (v)</code></a></h3> 2199
2200 <p>
2211 Receives a value of any type and 2201 Receives a value of any type and
2212 converts it to a string in a human-readable format. 2202 converts it to a string in a human-readable format.
2213 Floats always produce strings with some 2203
2214 floating-point indication (either a decimal dot or an exponent). 2204 <p>
2215 (For complete control of how numbers are converted, 2205 If the metatable of <tt>v</tt> has a <tt>"__to_string"</tt> field,
2216 use <a href="#pdf-string.format"><code>string.format</code></a>.) 2206 then <tt>to_string</tt> calls the corresponding value
2217 2207 with <tt>v</tt> as argument,
2218
2219 <p>
2220 If the metatable of <code>v</code> has a <code>"__to_string"</code> field,
2221 then <code>tostring</code> calls the corresponding value
2222 with <code>v</code> as argument,
2223 and uses the result of the call as its result. 2208 and uses the result of the call as its result.
2224 2209
2225 2210
2226 2211
2227 2212 <h4 margin-top="1em"><a name="Luan.type"><tt>Luan.type (v)</tt></a></h4>
2228 <p> 2213
2229 <hr><h3><a name="pdf-type"><code>type (v)</code></a></h3> 2214 <p>
2230 Returns the type of its only argument, coded as a string. 2215 Returns the type of its only argument, coded as a string.
2231 The possible results of this function are 2216 The possible results of this function are
2232 "<code>nil</code>" (a string, not the value <b>nil</b>), 2217 "<tt>nil</tt>" (a string, not the value <b>nil</b>),
2233 "<code>number</code>", 2218 "<tt>number</tt>",
2234 "<code>string</code>", 2219 "<tt>string</tt>",
2235 "<code>boolean</code>", 2220 "<tt>binary</tt>",
2236 "<code>table</code>", 2221 "<tt>boolean</tt>",
2237 "<code>function</code>", 2222 "<tt>table</tt>",
2238 "<code>thread</code>", 2223 "<tt>function</tt>",
2239 and "<code>userdata</code>". 2224 and "<tt>userdata</tt>".
2240 2225
2241 2226
2242 2227
2243 2228 <h4 margin-top="1em"><a name="Luan.VERSION"><tt>Luan.VERSION</tt></a></h4>
2244 <p> 2229
2245 <hr><h3><a name="pdf-_VERSION"><code>_VERSION</code></a></h3> 2230 <p>
2246 A global variable (not a function) that 2231 A global variable (not a function) that
2247 holds a string containing the current interpreter version. 2232 holds a string containing the current interpreter version.
2248 The current value of this variable is "<code>Lua 5.3</code>". 2233 The current value of this variable is "<tt>Luan 0.8</tt>".
2249
2250
2251
2252
2253 <p>
2254 <hr><h3><a name="pdf-xpcall"><code>xpcall (f, msgh [, arg1, &middot;&middot;&middot;])</code></a></h3>
2255
2256
2257 <p>
2258 This function is similar to <a href="#pdf-pcall"><code>pcall</code></a>,
2259 except that it sets a new message handler <code>msgh</code>.
2260
2261
2262
2263
2264
2265
2266
2267 <h2>6.2 &ndash; <a name="6.2">Coroutine Manipulation</a></h2>
2268
2269 <p>
2270 The operations related to coroutines comprise a sub-library of
2271 the basic library and come inside the table <a name="pdf-coroutine"><code>coroutine</code></a>.
2272 See <a href="#2.6">&sect;2.6</a> for a general description of coroutines.
2273
2274
2275 <p>
2276 <hr><h3><a name="pdf-coroutine.create"><code>coroutine.create (f)</code></a></h3>
2277
2278
2279 <p>
2280 Creates a new coroutine, with body <code>f</code>.
2281 <code>f</code> must be a Lua function.
2282 Returns this new coroutine,
2283 an object with type <code>"thread"</code>.
2284
2285
2286
2287
2288 <p>
2289 <hr><h3><a name="pdf-coroutine.isyieldable"><code>coroutine.isyieldable ()</code></a></h3>
2290
2291
2292 <p>
2293 Returns true when the running coroutine can yield.
2294
2295
2296 <p>
2297 A running coroutine is yieldable if it is not the main thread and
2298 it is not inside a non-yieldable C function.
2299
2300
2301
2302
2303 <p>
2304 <hr><h3><a name="pdf-coroutine.resume"><code>coroutine.resume (co [, val1, &middot;&middot;&middot;])</code></a></h3>
2305
2306
2307 <p>
2308 Starts or continues the execution of coroutine <code>co</code>.
2309 The first time you resume a coroutine,
2310 it starts running its body.
2311 The values <code>val1</code>, ... are passed
2312 as the arguments to the body function.
2313 If the coroutine has yielded,
2314 <code>resume</code> restarts it;
2315 the values <code>val1</code>, ... are passed
2316 as the results from the yield.
2317
2318
2319 <p>
2320 If the coroutine runs without any errors,
2321 <code>resume</code> returns <b>true</b> plus any values passed to <code>yield</code>
2322 (when the coroutine yields) or any values returned by the body function
2323 (when the coroutine terminates).
2324 If there is any error,
2325 <code>resume</code> returns <b>false</b> plus the error message.
2326
2327
2328
2329
2330 <p>
2331 <hr><h3><a name="pdf-coroutine.running"><code>coroutine.running ()</code></a></h3>
2332
2333
2334 <p>
2335 Returns the running coroutine plus a boolean,
2336 true when the running coroutine is the main one.
2337
2338
2339
2340
2341 <p>
2342 <hr><h3><a name="pdf-coroutine.status"><code>coroutine.status (co)</code></a></h3>
2343
2344
2345 <p>
2346 Returns the status of coroutine <code>co</code>, as a string:
2347 <code>"running"</code>,
2348 if the coroutine is running (that is, it called <code>status</code>);
2349 <code>"suspended"</code>, if the coroutine is suspended in a call to <code>yield</code>,
2350 or if it has not started running yet;
2351 <code>"normal"</code> if the coroutine is active but not running
2352 (that is, it has resumed another coroutine);
2353 and <code>"dead"</code> if the coroutine has finished its body function,
2354 or if it has stopped with an error.
2355
2356
2357
2358
2359 <p>
2360 <hr><h3><a name="pdf-coroutine.wrap"><code>coroutine.wrap (f)</code></a></h3>
2361
2362
2363 <p>
2364 Creates a new coroutine, with body <code>f</code>.
2365 <code>f</code> must be a Lua function.
2366 Returns a function that resumes the coroutine each time it is called.
2367 Any arguments passed to the function behave as the
2368 extra arguments to <code>resume</code>.
2369 Returns the same values returned by <code>resume</code>,
2370 except the first boolean.
2371 In case of error, propagates the error.
2372
2373
2374
2375
2376 <p>
2377 <hr><h3><a name="pdf-coroutine.yield"><code>coroutine.yield (&middot;&middot;&middot;)</code></a></h3>
2378
2379
2380 <p>
2381 Suspends the execution of the calling coroutine.
2382 Any arguments to <code>yield</code> are passed as extra results to <code>resume</code>.
2383 2234
2384 2235
2385 2236
2386 2237
2387 2238