repo/luan: website/src/manual.html.luan annotate

annotate website/src/manual.html.luan @ 503:92c3d22745b8

make _ENV optional

author	Franklin Schmidt <fschmidt@gmail.com>
date	Wed, 20 May 2015 23:24:46 -0600
parents	d3183a330ff5
children	7bc63886d4f2

rev	line source
478 eb6d90fb0b5c documentation Franklin Schmidt <fschmidt@gmail.com> parents: 476 diff changeset	1 local Luan = require "luan:Luan"
386 db23f654f87d make all of website use luan Franklin Schmidt <fschmidt@gmail.com> parents: 382 diff changeset	2 local Io = require "luan:Io"
db23f654f87d make all of website use luan Franklin Schmidt <fschmidt@gmail.com> parents: 382 diff changeset	3 local Html = require "luan:Html"
494 2b9bc97f0439 change luan:web to luan:http Franklin Schmidt <fschmidt@gmail.com> parents: 492 diff changeset	4 local Http = require "luan:http/Http"
387 23d075ce1e48 add website/src/Shared.luan Franklin Schmidt <fschmidt@gmail.com> parents: 386 diff changeset	5 local Shared = require "site:/Shared"
386 db23f654f87d make all of website use luan Franklin Schmidt <fschmidt@gmail.com> parents: 382 diff changeset	6
503 92c3d22745b8 make _ENV optional Franklin Schmidt <fschmidt@gmail.com> parents: 502 diff changeset	7 local M = {}
92c3d22745b8 make _ENV optional Franklin Schmidt <fschmidt@gmail.com> parents: 502 diff changeset	8
92c3d22745b8 make _ENV optional Franklin Schmidt <fschmidt@gmail.com> parents: 502 diff changeset	9 local heading_options = [[margin-top="2em" margin-bottom=".6em" textcolor="#233E93"]]
92c3d22745b8 make _ENV optional Franklin Schmidt <fschmidt@gmail.com> parents: 502 diff changeset	10 M.heading_options = heading_options
92c3d22745b8 make _ENV optional Franklin Schmidt <fschmidt@gmail.com> parents: 502 diff changeset	11
92c3d22745b8 make _ENV optional Franklin Schmidt <fschmidt@gmail.com> parents: 502 diff changeset	12 function M.respond()
386 db23f654f87d make all of website use luan Franklin Schmidt <fschmidt@gmail.com> parents: 382 diff changeset	13 Io.stdout = Http.response.text_writer()
391 2f5cc9c2cbf0 replace Html.simply_html_page with simply_html_head and simply_html_body_bottom Franklin Schmidt <fschmidt@gmail.com> parents: 389 diff changeset	14 %>
2f5cc9c2cbf0 replace Html.simply_html_page with simply_html_head and simply_html_body_bottom Franklin Schmidt <fschmidt@gmail.com> parents: 389 diff changeset	15 <html>
2f5cc9c2cbf0 replace Html.simply_html_page with simply_html_head and simply_html_body_bottom Franklin Schmidt <fschmidt@gmail.com> parents: 389 diff changeset	16 <head>
2f5cc9c2cbf0 replace Html.simply_html_page with simply_html_head and simply_html_body_bottom Franklin Schmidt <fschmidt@gmail.com> parents: 389 diff changeset	17 <% Html.simply_html_head() %>
2f5cc9c2cbf0 replace Html.simply_html_page with simply_html_head and simply_html_body_bottom Franklin Schmidt <fschmidt@gmail.com> parents: 389 diff changeset	18 <title>Luan Reference Manual</title>
2f5cc9c2cbf0 replace Html.simply_html_page with simply_html_head and simply_html_body_bottom Franklin Schmidt <fschmidt@gmail.com> parents: 389 diff changeset	19 </head>
2f5cc9c2cbf0 replace Html.simply_html_page with simply_html_head and simply_html_body_bottom Franklin Schmidt <fschmidt@gmail.com> parents: 389 diff changeset	20 <body>
386 db23f654f87d make all of website use luan Franklin Schmidt <fschmidt@gmail.com> parents: 382 diff changeset	21
372 f08cefa4594c start editing manual Franklin Schmidt <fschmidt@gmail.com> parents: 371 diff changeset	22 <div container>
387 23d075ce1e48 add website/src/Shared.luan Franklin Schmidt <fschmidt@gmail.com> parents: 386 diff changeset	23 <% Shared.header() %>
372 f08cefa4594c start editing manual Franklin Schmidt <fschmidt@gmail.com> parents: 371 diff changeset	24
f08cefa4594c start editing manual Franklin Schmidt <fschmidt@gmail.com> parents: 371 diff changeset	25 <h1>Luan Reference Manual</h1>
f08cefa4594c start editing manual Franklin Schmidt <fschmidt@gmail.com> parents: 371 diff changeset	26
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	27 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	28 <small>
372 f08cefa4594c start editing manual Franklin Schmidt <fschmidt@gmail.com> parents: 371 diff changeset	29 Original copyright © 2015 Lua.org, PUC-Rio.
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	30 Freely available under the terms of the
372 f08cefa4594c start editing manual Franklin Schmidt <fschmidt@gmail.com> parents: 371 diff changeset	31 <a href="http://www.lua.org/license.html">Lua license</a>.
f08cefa4594c start editing manual Franklin Schmidt <fschmidt@gmail.com> parents: 371 diff changeset	32 Modified for Luan.
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	33 </small>
372 f08cefa4594c start editing manual Franklin Schmidt <fschmidt@gmail.com> parents: 371 diff changeset	34 </p>
f08cefa4594c start editing manual Franklin Schmidt <fschmidt@gmail.com> parents: 371 diff changeset	35
f08cefa4594c start editing manual Franklin Schmidt <fschmidt@gmail.com> parents: 371 diff changeset	36 <hr/>
f08cefa4594c start editing manual Franklin Schmidt <fschmidt@gmail.com> parents: 371 diff changeset	37
f08cefa4594c start editing manual Franklin Schmidt <fschmidt@gmail.com> parents: 371 diff changeset	38 <h2>Contents</h2>
f08cefa4594c start editing manual Franklin Schmidt <fschmidt@gmail.com> parents: 371 diff changeset	39
f08cefa4594c start editing manual Franklin Schmidt <fschmidt@gmail.com> parents: 371 diff changeset	40 <div margin-bottom="1em"><a href="#intro">Introduction</a></div>
f08cefa4594c start editing manual Franklin Schmidt <fschmidt@gmail.com> parents: 371 diff changeset	41
373 571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	42 <div margin-bottom="1em">
571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	43 <a href="#basic">Basic Concepts</a>
571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	44 <ul>
571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	45 <li><a href="#types">Values and Types</a></li>
571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	46 <li><a href="#env">Environments</a></li>
571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	47 <li><a href="#error">Error Handling</a></li>
571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	48 <li><a href="#meta">Metatables and Metamethods</a></li>
380 6c6c3537035e work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 373 diff changeset	49 <li><a href="#gc">Garbage Collection</a></li>
6c6c3537035e work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 373 diff changeset	50 </ul>
6c6c3537035e work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 373 diff changeset	51 </div>
6c6c3537035e work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 373 diff changeset	52
6c6c3537035e work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 373 diff changeset	53 <div margin-bottom="1em">
6c6c3537035e work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 373 diff changeset	54 <a href="#lang">The Language</a>
6c6c3537035e work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 373 diff changeset	55 <ul>
6c6c3537035e work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 373 diff changeset	56 <li><a href="#lex">Lexical Conventions</a></li>
6c6c3537035e work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 373 diff changeset	57 <li><a href="#vars">Variables</a></li>
389 497d4ef0a89f documentation work Franklin Schmidt <fschmidt@gmail.com> parents: 387 diff changeset	58 <li>
497d4ef0a89f documentation work Franklin Schmidt <fschmidt@gmail.com> parents: 387 diff changeset	59 <a href="#stmts">Statements</a>
497d4ef0a89f documentation work Franklin Schmidt <fschmidt@gmail.com> parents: 387 diff changeset	60 <ul>
497d4ef0a89f documentation work Franklin Schmidt <fschmidt@gmail.com> parents: 387 diff changeset	61 <li><a href="#blocks">Blocks</a></li>
395 a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	62 <li><a href="#chunks">Chunks</a></li>
a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	63 <li><a href="#assignment">Assignment</a></li>
a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	64 <li><a href="#control">Control Structures</a></li>
a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	65 <li><a href="#for">For Statement</a></li>
a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	66 <li><a href="#fn_stmt">Function Calls as Statements</a></li>
a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	67 <li><a href="#local_stmt">Local Declarations</a></li>
465 47c7de1f2322 documentation work Franklin Schmidt <fschmidt@gmail.com> parents: 464 diff changeset	68 <li><a href="#template_stmt">Template Statements</a></li>
395 a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	69 </ul>
a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	70 </li>
a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	71 <li>
a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	72 <a href="#expressions">Expressions</a>
a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	73 <ul>
a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	74 <li><a href="#arithmetic">Arithmetic Operators</a></li>
396 ba8b0aae6453 work on manual; Franklin Schmidt <fschmidt@gmail.com> parents: 395 diff changeset	75 <li><a href="#conversions">Coercions and Conversions</a></li>
ba8b0aae6453 work on manual; Franklin Schmidt <fschmidt@gmail.com> parents: 395 diff changeset	76 <li><a href="#relational">Relational Operators</a></li>
ba8b0aae6453 work on manual; Franklin Schmidt <fschmidt@gmail.com> parents: 395 diff changeset	77 <li><a href="#logical_ops">Logical Operators</a></li>
ba8b0aae6453 work on manual; Franklin Schmidt <fschmidt@gmail.com> parents: 395 diff changeset	78 <li><a href="#concatenation">Concatenation</a></li>
ba8b0aae6453 work on manual; Franklin Schmidt <fschmidt@gmail.com> parents: 395 diff changeset	79 <li><a href="#length">The Length Operator</a></li>
ba8b0aae6453 work on manual; Franklin Schmidt <fschmidt@gmail.com> parents: 395 diff changeset	80 <li><a href="#precedence">Precedence</a></li>
ba8b0aae6453 work on manual; Franklin Schmidt <fschmidt@gmail.com> parents: 395 diff changeset	81 <li><a href="#constructors">Table Constructors</a></li>
417 a40e99cf0b0b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 396 diff changeset	82 <li><a href="#fn_calls">Function Calls</a></li>
a40e99cf0b0b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 396 diff changeset	83 <li><a href="#fn_def">Function Definitions</a></li>
465 47c7de1f2322 documentation work Franklin Schmidt <fschmidt@gmail.com> parents: 464 diff changeset	84 <li><a href="#template_expr">Template Expressions</a></li>
389 497d4ef0a89f documentation work Franklin Schmidt <fschmidt@gmail.com> parents: 387 diff changeset	85 </ul>
497d4ef0a89f documentation work Franklin Schmidt <fschmidt@gmail.com> parents: 387 diff changeset	86 </li>
464 eddf7c73373b fix references in the manual Franklin Schmidt <fschmidt@gmail.com> parents: 429 diff changeset	87 <li><a href="#visibility">Visibility Rules</a></li>
373 571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	88 </ul>
571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	89 </div>
571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	90
468 9b51e2413cab documentation Franklin Schmidt <fschmidt@gmail.com> parents: 465 diff changeset	91 <div margin-bottom="1em">
9b51e2413cab documentation Franklin Schmidt <fschmidt@gmail.com> parents: 465 diff changeset	92 <a href="#libs">Standard Libraries</a>
9b51e2413cab documentation Franklin Schmidt <fschmidt@gmail.com> parents: 465 diff changeset	93 <ul>
9b51e2413cab documentation Franklin Schmidt <fschmidt@gmail.com> parents: 465 diff changeset	94 <li><a href="#default_lib">Default Environment</a></li>
470 5627eb637eb4 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 469 diff changeset	95 <li><a href="#luan_lib">Basic Functions</a></li>
476 cd22e4694ea3 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 475 diff changeset	96 <li><a href="#package_lib">Modules</a></li>
468 9b51e2413cab documentation Franklin Schmidt <fschmidt@gmail.com> parents: 465 diff changeset	97 </ul>
9b51e2413cab documentation Franklin Schmidt <fschmidt@gmail.com> parents: 465 diff changeset	98 </div>
9b51e2413cab documentation Franklin Schmidt <fschmidt@gmail.com> parents: 465 diff changeset	99
372 f08cefa4594c start editing manual Franklin Schmidt <fschmidt@gmail.com> parents: 371 diff changeset	100 <hr/>
f08cefa4594c start editing manual Franklin Schmidt <fschmidt@gmail.com> parents: 371 diff changeset	101
373 571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	102
479 1285c52ea9d4 add manual heading_options Franklin Schmidt <fschmidt@gmail.com> parents: 478 diff changeset	103 <h2 <%=heading_options%> ><a name="intro">Introduction</a></h2>
372 f08cefa4594c start editing manual Franklin Schmidt <fschmidt@gmail.com> parents: 371 diff changeset	104
f08cefa4594c start editing manual Franklin Schmidt <fschmidt@gmail.com> parents: 371 diff changeset	105 <p>Luan is a high level programming language based on <a href="http://www.lua.org">Lua</a>. A great strength of Lua is its simplicity and Luan takes this even further, being even simpler than Lua. The goal is to provide a simple programming language for the casual programmer with as few concepts as possible so that one can quickly learn the language and then easily understand any code written in Luan.</p>
f08cefa4594c start editing manual Franklin Schmidt <fschmidt@gmail.com> parents: 371 diff changeset	106
f08cefa4594c start editing manual Franklin Schmidt <fschmidt@gmail.com> parents: 371 diff changeset	107 <p>Luan is implemented in Java and is tightly coupled with Java. So it makes a great scripting language for Java programmers.</p>
f08cefa4594c start editing manual Franklin Schmidt <fschmidt@gmail.com> parents: 371 diff changeset	108
f08cefa4594c start editing manual Franklin Schmidt <fschmidt@gmail.com> parents: 371 diff changeset	109 <p>Unlike Lua which is meant to be embedded, Luan is meant to be a full scripting language. This done not by adding feature to Luan, but rather by providing a complete set of libraries.</p>
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	110
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	111
479 1285c52ea9d4 add manual heading_options Franklin Schmidt <fschmidt@gmail.com> parents: 478 diff changeset	112 <h2 <%=heading_options%> ><a name="basic">Basic Concepts</a></h2>
373 571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	113
571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	114 <p>This section describes the basic concepts of the language.</p>
571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	115
479 1285c52ea9d4 add manual heading_options Franklin Schmidt <fschmidt@gmail.com> parents: 478 diff changeset	116 <h3 <%=heading_options%> ><a name="types">Values and Types</a></h3>
373 571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	117
571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	118 <p>
571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	119 Luan is a <i>dynamically typed language</i>.
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	120 This means that
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	121 variables do not have types; only values do.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	122 There are no type definitions in the language.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	123 All values carry their own type.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	124
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	125
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	126 <p>
373 571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	127 All values in Luan are <i>first-class values</i>.
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	128 This means that all values can be stored in variables,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	129 passed as arguments to other functions, and returned as results.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	130
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	131
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	132 <p>
373 571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	133 There are eight basic types in Luan:
571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	134 <i>nil</i>, <i>boolean</i>, <i>number</i>,
571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	135 <i>string</i>, <i>binary</i>, <i>function</i>, <i>userdata</i>,
571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	136 and <i>table</i>.
571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	137 <i>Nil</i> is the type of the value <b>nil</b>,
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	138 whose main property is to be different from any other value;
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	139 it usually represents the absence of a useful value.
373 571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	140 <i>Nil</i> is implemented as the Java value <i>null</i>.
571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	141 <i>Boolean</i> is the type of the values <b>false</b> and <b>true</b>.
571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	142 <i>Boolean</i> is implemented as the Java class <i>Boolean</i>.
571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	143 <i>Number</i> represents both
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	144 integer numbers and real (floating-point) numbers.
373 571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	145 <i>Number</i> is implemented as the Java class <i>Number</i>. Any Java subclass of <i>Number</i> is allowed and this is invisible to the Luan user. Operations on numbers follow the same rules of
571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	146 the underlying Java implementation.
571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	147
571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	148 <i>String</i> is implemented as the Java class <i>String</i>.
571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	149 <i>Binary</i> is implemented as the Java type <i>byte[]</i>.
571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	150
571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	151
571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	152 <p>
571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	153 Luan can call (and manipulate) functions written in Luan and
464 eddf7c73373b fix references in the manual Franklin Schmidt <fschmidt@gmail.com> parents: 429 diff changeset	154 functions written in Java (see <a href="#fn_calls">Function Calls</a>).
373 571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	155 Both are represented by the type <i>function</i>.
571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	156
571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	157
571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	158 <p>
571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	159 The type <i>userdata</i> is provided to allow arbitrary Java objects to
571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	160 be stored in Luan variables.
571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	161 A userdata value is a Java object that isn't one of the standard Luan types.
571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	162 Userdata has no predefined operations in Luan,
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	163 except assignment and identity test.
373 571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	164 Userdata is useful then Java access is enabled in Luan
571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	165
571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	166
571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	167
571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	168 <p>
571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	169 The type <i>table</i> implements associative arrays,
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	170 that is, arrays that can be indexed not only with numbers,
373 571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	171 but with any Luan value except <b>nil</b>.
571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	172 Tables can be <i>heterogeneous</i>;
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	173 that is, they can contain values of all types (except <b>nil</b>).
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	174 Any key with value <b>nil</b> is not considered part of the table.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	175 Conversely, any key that is not part of a table has
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	176 an associated value <b>nil</b>.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	177
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	178
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	179 <p>
373 571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	180 Tables are the sole data-structuring mechanism in Luan;
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	181 they can be used to represent ordinary arrays, sequences,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	182 symbol tables, sets, records, graphs, trees, etc.
373 571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	183 To represent records, Luan uses the field name as an index.
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	184 The language supports this representation by
373 571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	185 providing <tt>a.name</tt> as syntactic sugar for <tt>a["name"]</tt>.
571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	186 There are several convenient ways to create tables in Luan
464 eddf7c73373b fix references in the manual Franklin Schmidt <fschmidt@gmail.com> parents: 429 diff changeset	187 (see <a href="#constructors">Table Constructors</a>).
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	188
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	189
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	190 <p>
373 571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	191 We use the term <i>sequence</i> to denote a table where
571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	192 the set of all positive numeric keys is equal to {1..<i>n</i>}
571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	193 for some non-negative integer <i>n</i>,
464 eddf7c73373b fix references in the manual Franklin Schmidt <fschmidt@gmail.com> parents: 429 diff changeset	194 which is called the length of the sequence (see <a href="#length">The Length Operator</a>).
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	195
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	196
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	197 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	198 Like indices,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	199 the values of table fields can be of any type.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	200 In particular,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	201 because functions are first-class values,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	202 table fields can contain functions.
464 eddf7c73373b fix references in the manual Franklin Schmidt <fschmidt@gmail.com> parents: 429 diff changeset	203 Thus tables can also carry <i>methods</i> (see <a href="#fn_def">Function Definitions</a>).
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	204
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	205
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	206 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	207 The indexing of tables follows
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	208 the definition of raw equality in the language.
373 571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	209 The expressions <tt>a[i]</tt> and <tt>a[j]</tt>
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	210 denote the same table element
373 571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	211 if and only if <tt>i</tt> and <tt>j</tt> are raw equal
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	212 (that is, equal without metamethods).
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	213 In particular, floats with integral values
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	214 are equal to their respective integers
373 571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	215 (e.g., <tt>1.0 == 1</tt>).
571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	216
571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	217
571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	218 <p>
571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	219 Luan values are <i>objects</i>:
571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	220 variables do not actually <i>contain</i> values,
571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	221 only <i>references</i> to them.
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	222 Assignment, parameter passing, and function returns
373 571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	223 always manipulate references to values;
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	224 these operations do not imply any kind of copy.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	225
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	226
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	227 <p>
478 eb6d90fb0b5c documentation Franklin Schmidt <fschmidt@gmail.com> parents: 476 diff changeset	228 The library function <a href="#Luan.type"><tt>Luan.type</tt></a> returns a string describing the type
eb6d90fb0b5c documentation Franklin Schmidt <fschmidt@gmail.com> parents: 476 diff changeset	229 of a given value.
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	230
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	231
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	232
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	233
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	234
479 1285c52ea9d4 add manual heading_options Franklin Schmidt <fschmidt@gmail.com> parents: 478 diff changeset	235 <h3 <%=heading_options%> ><a name="env">Environments</a></h3>
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	236
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	237 <p>
464 eddf7c73373b fix references in the manual Franklin Schmidt <fschmidt@gmail.com> parents: 429 diff changeset	238 As will be discussed in <a href="#vars">Variables</a> and <a href=#assignment">Assignment</a>,
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	239 any reference to a free name
373 571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	240 (that is, a name not bound to any declaration) <tt>var</tt>
571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	241 is syntactically translated to <tt>_ENV.var</tt>.
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	242 Moreover, every chunk is compiled in the scope of
464 eddf7c73373b fix references in the manual Franklin Schmidt <fschmidt@gmail.com> parents: 429 diff changeset	243 an external local variable named <tt>_ENV</tt> (see <a href="#chunks">Chunks</a>),
373 571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	244 so <tt>_ENV</tt> itself is never a free name in a chunk.
571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	245
571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	246
571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	247 <p>
571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	248 Despite the existence of this external <tt>_ENV</tt> variable and
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	249 the translation of free names,
373 571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	250 <tt>_ENV</tt> is a completely regular name.
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	251 In particular,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	252 you can define new variables and parameters with that name.
373 571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	253 Each reference to a free name uses the <tt>_ENV</tt> that is
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	254 visible at that point in the program,
464 eddf7c73373b fix references in the manual Franklin Schmidt <fschmidt@gmail.com> parents: 429 diff changeset	255 following the usual visibility rules of Luan (see <a href="#visibility">Visibility Rules</a>).
373 571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	256
571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	257
571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	258 <p>
571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	259 Any table used as the value of <tt>_ENV</tt> is called an <i>environment</i>.
571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	260
571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	261
571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	262 <p>
571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	263 When Luan loads a chunk,
571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	264 the default value for its <tt>_ENV</tt> is an empty table.
571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	265
571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	266 <p>
571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	267 Luan also provides all chunks with two other local values: <tt>require</tt> and <tt>java</tt>. These are functions used to load and access libraries and other modules.
571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	268
571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	269
571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	270
571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	271
479 1285c52ea9d4 add manual heading_options Franklin Schmidt <fschmidt@gmail.com> parents: 478 diff changeset	272 <h3 <%=heading_options%> ><a name="error">Error Handling</a></h3>
373 571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	273
571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	274 <p>
571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	275 Luan code can explicitly generate an error by calling the
478 eb6d90fb0b5c documentation Franklin Schmidt <fschmidt@gmail.com> parents: 476 diff changeset	276 <a href="#Luan.error"><tt>error</tt></a> function.
373 571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	277 If you need to catch errors in Luan,
478 eb6d90fb0b5c documentation Franklin Schmidt <fschmidt@gmail.com> parents: 476 diff changeset	278 you can use <a href="#Luan.pcall"><tt>pcall</tt></a> or <a href="#Luan.try"><tt>try</tt></a>
373 571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	279 to call a given function in <i>protected mode</i>.
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	280
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	281
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	282 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	283 Whenever there is an error,
482 7e9fcfbf22ec documentation Franklin Schmidt <fschmidt@gmail.com> parents: 479 diff changeset	284 an <i>error table</i>
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	285 is propagated with information about the error.
482 7e9fcfbf22ec documentation Franklin Schmidt <fschmidt@gmail.com> parents: 479 diff changeset	286 See <a href="#Luan.new_error"><tt>Luan.new_error</tt></a>.
373 571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	287
571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	288
571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	289
479 1285c52ea9d4 add manual heading_options Franklin Schmidt <fschmidt@gmail.com> parents: 478 diff changeset	290 <h3 <%=heading_options%> ><a name="meta">Metatables and Metamethods</a></h3>
373 571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	291
571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	292 <p>
571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	293 Every table in Luan can have a <i>metatable</i>.
571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	294 This <i>metatable</i> is an ordinary Luan table
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	295 that defines the behavior of the original value
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	296 under certain special operations.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	297 You can change several aspects of the behavior
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	298 of operations over a value by setting specific fields in its metatable.
373 571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	299 For instance, when a table is the operand of an addition,
571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	300 Luan checks for a function in the field "<tt>__add</tt>" of the table's metatable.
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	301 If it finds one,
373 571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	302 Luan calls this function to perform the addition.
571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	303
571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	304
571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	305 <p>
571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	306 The keys in a metatable are derived from the <i>event</i> names;
571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	307 the corresponding values are called <ii>metamethods</i>.
571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	308 In the previous example, the event is <tt>"add"</tt>
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	309 and the metamethod is the function that performs the addition.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	310
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	311
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	312 <p>
373 571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	313 You can query the metatable of any table
478 eb6d90fb0b5c documentation Franklin Schmidt <fschmidt@gmail.com> parents: 476 diff changeset	314 using the <a href="#Luan.get_metatable"><tt>get_metatable</tt></a> function.
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	315
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	316
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	317 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	318 You can replace the metatable of tables
478 eb6d90fb0b5c documentation Franklin Schmidt <fschmidt@gmail.com> parents: 476 diff changeset	319 using the <a href="#Luan.set_metatable"><tt>set_metatable</tt></a> function.
373 571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	320
571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	321
571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	322 <p>
571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	323 A metatable controls how a table behaves in
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	324 arithmetic operations, bitwise operations,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	325 order comparisons, concatenation, length operation, calls, and indexing.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	326
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	327
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	328 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	329 A detailed list of events controlled by metatables is given next.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	330 Each operation is identified by its corresponding event name.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	331 The key for each event is a string with its name prefixed by
373 571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	332 two underscores, '<tt>__</tt>';
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	333 for instance, the key for operation "add" is the
373 571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	334 string "<tt>__add</tt>".
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	335 Note that queries for metamethods are always raw;
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	336 the access to a metamethod does not invoke other metamethods.
373 571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	337 You can emulate how Luan queries a metamethod for an object <tt>obj</tt>
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	338 with the following code:
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	339
382 8557581740db added tutorial Franklin Schmidt <fschmidt@gmail.com> parents: 380 diff changeset	340 <p><tt><pre>
373 571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	341 raw_get(get_metatable(obj) or {}, "__" .. event_name)
382 8557581740db added tutorial Franklin Schmidt <fschmidt@gmail.com> parents: 380 diff changeset	342 </pre></tt></p>
373 571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	343
571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	344 <p>
571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	345 Here are the events:
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	346
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	347 <ul>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	348
502 d3183a330ff5 improve the __index metamethod to work with any type; Franklin Schmidt <fschmidt@gmail.com> parents: 495 diff changeset	349 <li><p><b>"add": </b>
373 571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	350 the <tt>+</tt> operation.
571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	351
571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	352 If any operand for an addition is a table,
571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	353 Luan will try to call a metamethod.
571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	354 First, Luan will check the first operand (even if it is valid).
571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	355 If that operand does not define a metamethod for the "<tt>__add</tt>" event,
571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	356 then Luan will check the second operand.
571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	357 If Luan can find a metamethod,
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	358 it calls the metamethod with the two operands as arguments,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	359 and the result of the call
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	360 (adjusted to one value)
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	361 is the result of the operation.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	362 Otherwise,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	363 it raises an error.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	364 </li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	365
502 d3183a330ff5 improve the __index metamethod to work with any type; Franklin Schmidt <fschmidt@gmail.com> parents: 495 diff changeset	366 <li><p><b>"sub": </b>
373 571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	367 the <tt>-</tt> operation.
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	368
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	369 Behavior similar to the "add" operation.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	370 </li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	371
502 d3183a330ff5 improve the __index metamethod to work with any type; Franklin Schmidt <fschmidt@gmail.com> parents: 495 diff changeset	372 <li><p><b>"mul": </b>
373 571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	373 the <tt>*</tt> operation.
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	374
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	375 Behavior similar to the "add" operation.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	376 </li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	377
502 d3183a330ff5 improve the __index metamethod to work with any type; Franklin Schmidt <fschmidt@gmail.com> parents: 495 diff changeset	378 <li><p><b>"div": </b>
373 571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	379 the <tt>/</tt> operation.
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	380
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	381 Behavior similar to the "add" operation.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	382 </li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	383
502 d3183a330ff5 improve the __index metamethod to work with any type; Franklin Schmidt <fschmidt@gmail.com> parents: 495 diff changeset	384 <li><p><b>"mod": </b>
373 571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	385 the <tt>%</tt> operation.
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	386
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	387 Behavior similar to the "add" operation.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	388 </li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	389
502 d3183a330ff5 improve the __index metamethod to work with any type; Franklin Schmidt <fschmidt@gmail.com> parents: 495 diff changeset	390 <li><p><b>"pow": </b>
373 571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	391 the <tt>^</tt> (exponentiation) operation.
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	392
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	393 Behavior similar to the "add" operation.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	394 </li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	395
502 d3183a330ff5 improve the __index metamethod to work with any type; Franklin Schmidt <fschmidt@gmail.com> parents: 495 diff changeset	396 <li><p><b>"unm": </b>
373 571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	397 the <tt>-</tt> (unary minus) operation.
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	398
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	399 Behavior similar to the "add" operation.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	400 </li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	401
502 d3183a330ff5 improve the __index metamethod to work with any type; Franklin Schmidt <fschmidt@gmail.com> parents: 495 diff changeset	402 <li><p><b>"concat": </b>
373 571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	403 the <tt>..</tt> (concatenation) operation.
571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	404
571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	405 Behavior similar to the "add" operation.
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	406 </li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	407
502 d3183a330ff5 improve the __index metamethod to work with any type; Franklin Schmidt <fschmidt@gmail.com> parents: 495 diff changeset	408 <li><p><b>"len": </b>
373 571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	409 the <tt>#</tt> (length) operation.
571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	410
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	411 If there is a metamethod,
373 571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	412 Luan calls it with the object as argument,
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	413 and the result of the call
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	414 (always adjusted to one value)
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	415 is the result of the operation.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	416 If there is no metamethod but the object is a table,
464 eddf7c73373b fix references in the manual Franklin Schmidt <fschmidt@gmail.com> parents: 429 diff changeset	417 then Luan uses the table length operation (see <a href="#length">The Length Operator</a>).
373 571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	418 Otherwise, Luan raises an error.
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	419 </li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	420
502 d3183a330ff5 improve the __index metamethod to work with any type; Franklin Schmidt <fschmidt@gmail.com> parents: 495 diff changeset	421 <li><p><b>"eq": </b>
373 571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	422 the <tt>==</tt> (equal) operation.
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	423
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	424 Behavior similar to the "add" operation,
373 571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	425 except that Luan will try a metamethod only when the values
571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	426 being compared are both tables
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	427 and they are not primitively equal.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	428 The result of the call is always converted to a boolean.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	429 </li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	430
502 d3183a330ff5 improve the __index metamethod to work with any type; Franklin Schmidt <fschmidt@gmail.com> parents: 495 diff changeset	431 <li><p><b>"lt": </b>
373 571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	432 the <tt><</tt> (less than) operation.
571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	433
571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	434 Behavior similar to the "add" operation.
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	435 The result of the call is always converted to a boolean.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	436 </li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	437
502 d3183a330ff5 improve the __index metamethod to work with any type; Franklin Schmidt <fschmidt@gmail.com> parents: 495 diff changeset	438 <li><p><b>"le": </b>
373 571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	439 the <tt><=</tt> (less equal) operation.
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	440
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	441 Unlike other operations,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	442 The less-equal operation can use two different events.
373 571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	443 First, Luan looks for the "<tt>__le</tt>" metamethod in both operands,
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	444 like in the "lt" operation.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	445 If it cannot find such a metamethod,
373 571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	446 then it will try the "<tt>__lt</tt>" event,
571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	447 assuming that <tt>a <= b</tt> is equivalent to <tt>not (b < a)</tt>.
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	448 As with the other comparison operators,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	449 the result is always a boolean.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	450 </li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	451
502 d3183a330ff5 improve the __index metamethod to work with any type; Franklin Schmidt <fschmidt@gmail.com> parents: 495 diff changeset	452 <li><p><b>"index": </b>
373 571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	453 The indexing access <tt>table[key]</tt>.
571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	454
571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	455 This event happens
571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	456 when <tt>key</tt> is not present in <tt>table</tt>.
571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	457 The metamethod is looked up in <tt>table</tt>.
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	458
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	459
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	460 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	461 Despite the name,
502 d3183a330ff5 improve the __index metamethod to work with any type; Franklin Schmidt <fschmidt@gmail.com> parents: 495 diff changeset	462 the metamethod for this event can be any type.
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	463 If it is a function,
373 571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	464 it is called with <tt>table</tt> and <tt>key</tt> as arguments.
502 d3183a330ff5 improve the __index metamethod to work with any type; Franklin Schmidt <fschmidt@gmail.com> parents: 495 diff changeset	465 Otherwise
d3183a330ff5 improve the __index metamethod to work with any type; Franklin Schmidt <fschmidt@gmail.com> parents: 495 diff changeset	466 the final result is the result of indexing this metamethod object with <tt>key</tt>.
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	467 (This indexing is regular, not raw,
502 d3183a330ff5 improve the __index metamethod to work with any type; Franklin Schmidt <fschmidt@gmail.com> parents: 495 diff changeset	468 and therefore can trigger another metamethod if the metamethod object is a table.)
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	469 </li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	470
502 d3183a330ff5 improve the __index metamethod to work with any type; Franklin Schmidt <fschmidt@gmail.com> parents: 495 diff changeset	471 <li><p><b>"new_index": </b>
373 571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	472 The indexing assignment <tt>table[key] = value</tt>.
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	473
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	474 Like the index event,
373 571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	475 this event happens when
571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	476 when <tt>key</tt> is not present in <tt>table</tt>.
571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	477 The metamethod is looked up in <tt>table</tt>.
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	478
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	479
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	480 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	481 Like with indexing,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	482 the metamethod for this event can be either a function or a table.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	483 If it is a function,
373 571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	484 it is called with <tt>table</tt>, <tt>key</tt>, and <tt>value</tt> as arguments.
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	485 If it is a table,
373 571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	486 Luan does an indexing assignment to this table with the same key and value.
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	487 (This assignment is regular, not raw,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	488 and therefore can trigger another metamethod.)
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	489
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	490
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	491 <p>
428 df95199ca4c0 rename __newindex to __new_index Franklin Schmidt <fschmidt@gmail.com> parents: 418 diff changeset	492 Whenever there is a "new_index" metamethod,
373 571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	493 Luan does not perform the primitive assignment.
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	494 (If necessary,
478 eb6d90fb0b5c documentation Franklin Schmidt <fschmidt@gmail.com> parents: 476 diff changeset	495 the metamethod itself can call <a href="#Luan.raw_set"><tt>raw_set</tt></a>
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	496 to do the assignment.)
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	497 </li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	498
502 d3183a330ff5 improve the __index metamethod to work with any type; Franklin Schmidt <fschmidt@gmail.com> parents: 495 diff changeset	499 <li><p><b>"call": </b>
373 571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	500 The call operation <tt>func(args)</tt>.
571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	501
571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	502 This event happens when Luan tries to call a table.
571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	503 The metamethod is looked up in <tt>func</tt>.
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	504 If present,
373 571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	505 the metamethod is called with <tt>func</tt> as its first argument,
571057b1666b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 372 diff changeset	506 followed by the arguments of the original call (<tt>args</tt>).
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	507 </li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	508
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	509 </ul>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	510
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	511
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	512
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	513
479 1285c52ea9d4 add manual heading_options Franklin Schmidt <fschmidt@gmail.com> parents: 478 diff changeset	514 <h3 <%=heading_options%> ><a name="gc">Garbage Collection</a></h3>
380 6c6c3537035e work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 373 diff changeset	515
6c6c3537035e work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 373 diff changeset	516 <p>
6c6c3537035e work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 373 diff changeset	517 Luan uses Java's garbage collection.
6c6c3537035e work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 373 diff changeset	518
6c6c3537035e work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 373 diff changeset	519
6c6c3537035e work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 373 diff changeset	520
6c6c3537035e work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 373 diff changeset	521
6c6c3537035e work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 373 diff changeset	522
479 1285c52ea9d4 add manual heading_options Franklin Schmidt <fschmidt@gmail.com> parents: 478 diff changeset	523 <h2 <%=heading_options%> ><a name="lang">The Language</a></h2>
380 6c6c3537035e work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 373 diff changeset	524
6c6c3537035e work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 373 diff changeset	525 <p>
6c6c3537035e work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 373 diff changeset	526 This section describes the lexis, the syntax, and the semantics of Luan.
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	527 In other words,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	528 this section describes
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	529 which tokens are valid,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	530 how they can be combined,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	531 and what their combinations mean.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	532
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	533
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	534 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	535 Language constructs will be explained using the usual extended BNF notation,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	536 in which
380 6c6c3537035e work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 373 diff changeset	537 {<i>a</i>} means 0 or more <i>a</i>'s, and
6c6c3537035e work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 373 diff changeset	538 [<i>a</i>] means an optional <i>a</i>.
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	539 Non-terminals are shown like non-terminal,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	540 keywords are shown like <b>kword</b>,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	541 and other terminal symbols are shown like ‘<b>=</b>’.
380 6c6c3537035e work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 373 diff changeset	542 The complete syntax of Luan can be found in <a href="#9">§9</a>
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	543 at the end of this manual.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	544
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	545
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	546
479 1285c52ea9d4 add manual heading_options Franklin Schmidt <fschmidt@gmail.com> parents: 478 diff changeset	547 <h3 <%=heading_options%> ><a name="lex">Lexical Conventions</a></h3>
380 6c6c3537035e work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 373 diff changeset	548
6c6c3537035e work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 373 diff changeset	549 <p>
6c6c3537035e work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 373 diff changeset	550 Luan ignores spaces and comments
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	551 between lexical elements (tokens),
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	552 except as delimiters between names and keywords.
380 6c6c3537035e work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 373 diff changeset	553 Luan generally considers the end of a line to be the end of a statement. This catches errors and encourages readability. The exception to this is in paranthesis ( <i>(...)</i>, <i>[...]</i>, and <i>{...}</i> ) where the end of line is treated as white space.
6c6c3537035e work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 373 diff changeset	554
6c6c3537035e work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 373 diff changeset	555 <p>
6c6c3537035e work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 373 diff changeset	556 <i>Names</i>
6c6c3537035e work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 373 diff changeset	557 (also called <i>identifiers</i>)
6c6c3537035e work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 373 diff changeset	558 in Luan can be any string of letters,
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	559 digits, and underscores,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	560 not beginning with a digit.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	561 Identifiers are used to name variables, table fields, and labels.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	562
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	563
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	564 <p>
380 6c6c3537035e work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 373 diff changeset	565 The following <i>keywords</i> are reserved
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	566 and cannot be used as names:
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	567
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	568
389 497d4ef0a89f documentation work Franklin Schmidt <fschmidt@gmail.com> parents: 387 diff changeset	569 <p><tt><pre>
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	570 and break do else elseif end
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	571 false for function goto if in
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	572 local nil not or repeat return
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	573 then true until while
389 497d4ef0a89f documentation work Franklin Schmidt <fschmidt@gmail.com> parents: 387 diff changeset	574 </pre></tt></p>
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	575
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	576 <p>
380 6c6c3537035e work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 373 diff changeset	577 Luan is a case-sensitive language:
6c6c3537035e work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 373 diff changeset	578 <tt>and</tt> is a reserved word, but <tt>And</tt> and <tt>AND</tt>
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	579 are two different, valid names.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	580
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	581
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	582 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	583 The following strings denote other tokens:
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	584
389 497d4ef0a89f documentation work Franklin Schmidt <fschmidt@gmail.com> parents: 387 diff changeset	585 <p><tt><pre>
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	586 + - * / % ^ #
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	587 & ~ \| << >> //
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	588 == ~= <= >= < > =
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	589 ( ) { } [ ] ::
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	590 ; : , . .. ...
389 497d4ef0a89f documentation work Franklin Schmidt <fschmidt@gmail.com> parents: 387 diff changeset	591 </pre></tt></p>
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	592
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	593 <p>
380 6c6c3537035e work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 373 diff changeset	594 <i>Literal strings</i>
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	595 can be delimited by matching single or double quotes,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	596 and can contain the following C-like escape sequences:
380 6c6c3537035e work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 373 diff changeset	597 '<tt>\a</tt>' (bell),
6c6c3537035e work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 373 diff changeset	598 '<tt>\b</tt>' (backspace),
6c6c3537035e work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 373 diff changeset	599 '<tt>\f</tt>' (form feed),
6c6c3537035e work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 373 diff changeset	600 '<tt>\n</tt>' (newline),
6c6c3537035e work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 373 diff changeset	601 '<tt>\r</tt>' (carriage return),
6c6c3537035e work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 373 diff changeset	602 '<tt>\t</tt>' (horizontal tab),
6c6c3537035e work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 373 diff changeset	603 '<tt>\v</tt>' (vertical tab),
6c6c3537035e work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 373 diff changeset	604 '<tt>\\</tt>' (backslash),
6c6c3537035e work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 373 diff changeset	605 '<tt>\"</tt>' (quotation mark [double quote]),
6c6c3537035e work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 373 diff changeset	606 and '<tt>\'</tt>' (apostrophe [single quote]).
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	607 A backslash followed by a real newline
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	608 results in a newline in the string.
380 6c6c3537035e work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 373 diff changeset	609 The escape sequence '<tt>\z</tt>' skips the following span
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	610 of white-space characters,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	611 including line breaks;
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	612 it is particularly useful to break and indent a long literal string
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	613 into multiple lines without adding the newlines and spaces
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	614 into the string contents.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	615
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	616
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	617 <p>
380 6c6c3537035e work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 373 diff changeset	618 Luan can specify any character in a literal string by its numerical value.
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	619 This can be done
380 6c6c3537035e work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 373 diff changeset	620 with the escape sequence <tt>\x<i>XX</i></tt>,
6c6c3537035e work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 373 diff changeset	621 where <i>XX</i> is a sequence of exactly two hexadecimal digits,
6c6c3537035e work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 373 diff changeset	622 or with the escape sequence <tt>\<i>ddd</i></tt>,
6c6c3537035e work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 373 diff changeset	623 where <i>ddd</i> is a sequence of up to three decimal digits.
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	624 (Note that if a decimal escape sequence is to be followed by a digit,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	625 it must be expressed using exactly three digits.)
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	626
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	627
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	628 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	629 Literal strings can also be defined using a long format
380 6c6c3537035e work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 373 diff changeset	630 enclosed by <i>long brackets</i>.
6c6c3537035e work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 373 diff changeset	631 We define an <i>opening long bracket of level <i>n</i></i> as an opening
6c6c3537035e work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 373 diff changeset	632 square bracket followed by <i>n</i> equal signs followed by another
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	633 opening square bracket.
380 6c6c3537035e work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 373 diff changeset	634 So, an opening long bracket of level 0 is written as <tt>[[</tt>,
6c6c3537035e work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 373 diff changeset	635 an opening long bracket of level 1 is written as <tt>[=[</tt>,
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	636 and so on.
380 6c6c3537035e work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 373 diff changeset	637 A <i>closing long bracket</i> is defined similarly;
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	638 for instance,
380 6c6c3537035e work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 373 diff changeset	639 a closing long bracket of level 4 is written as <tt>]====]</tt>.
6c6c3537035e work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 373 diff changeset	640 A <i>long literal</i> starts with an opening long bracket of any level and
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	641 ends at the first closing long bracket of the same level.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	642 It can contain any text except a closing bracket of the same level.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	643 Literals in this bracketed form can run for several lines,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	644 do not interpret any escape sequences,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	645 and ignore long brackets of any other level.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	646 Any kind of end-of-line sequence
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	647 (carriage return, newline, carriage return followed by newline,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	648 or newline followed by carriage return)
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	649 is converted to a simple newline.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	650
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	651
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	652 <p>
380 6c6c3537035e work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 373 diff changeset	653 Any character in a literal string not
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	654 explicitly affected by the previous rules represents itself.
380 6c6c3537035e work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 373 diff changeset	655 However, Luan opens files for parsing in text mode,
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	656 and the system file functions may have problems with
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	657 some control characters.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	658 So, it is safer to represent
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	659 non-text data as a quoted literal with
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	660 explicit escape sequences for non-text characters.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	661
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	662
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	663 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	664 For convenience,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	665 when the opening long bracket is immediately followed by a newline,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	666 the newline is not included in the string.
380 6c6c3537035e work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 373 diff changeset	667 As an example
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	668 the five literal strings below denote the same string:
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	669
389 497d4ef0a89f documentation work Franklin Schmidt <fschmidt@gmail.com> parents: 387 diff changeset	670 <p><tt><pre>
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	671 a = 'alo\n123"'
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	672 a = "alo\n123\""
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	673 a = '\97lo\10\04923"'
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	674 a = [[alo
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	675 123"]]
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	676 a = [==[
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	677 alo
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	678 123"]==]
389 497d4ef0a89f documentation work Franklin Schmidt <fschmidt@gmail.com> parents: 387 diff changeset	679 </pre></tt></p>
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	680
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	681 <p>
380 6c6c3537035e work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 373 diff changeset	682 A <i>numerical constant</i> (or <i>numeral</i>)
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	683 can be written with an optional fractional part
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	684 and an optional decimal exponent,
380 6c6c3537035e work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 373 diff changeset	685 marked by a letter '<tt>e</tt>' or '<tt>E</tt>'.
6c6c3537035e work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 373 diff changeset	686 Luan also accepts hexadecimal constants,
6c6c3537035e work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 373 diff changeset	687 which start with <tt>0x</tt> or <tt>0X</tt>.
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	688 Hexadecimal constants also accept an optional fractional part
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	689 plus an optional binary exponent,
380 6c6c3537035e work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 373 diff changeset	690 marked by a letter '<tt>p</tt>' or '<tt>P</tt>'.
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	691 A numeric constant with a fractional dot or an exponent
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	692 denotes a float;
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	693 otherwise it denotes an integer.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	694 Examples of valid integer constants are
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	695
389 497d4ef0a89f documentation work Franklin Schmidt <fschmidt@gmail.com> parents: 387 diff changeset	696 <p><tt><pre>
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	697 3 345 0xff 0xBEBADA
389 497d4ef0a89f documentation work Franklin Schmidt <fschmidt@gmail.com> parents: 387 diff changeset	698 </pre></tt></p>
382 8557581740db added tutorial Franklin Schmidt <fschmidt@gmail.com> parents: 380 diff changeset	699
8557581740db added tutorial Franklin Schmidt <fschmidt@gmail.com> parents: 380 diff changeset	700 <p>
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	701 Examples of valid float constants are
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	702
389 497d4ef0a89f documentation work Franklin Schmidt <fschmidt@gmail.com> parents: 387 diff changeset	703 <p><tt><pre>
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	704 3.0 3.1416 314.16e-2 0.31416E1 34e1
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	705 0x0.1E 0xA23p-4 0X1.921FB54442D18P+1
389 497d4ef0a89f documentation work Franklin Schmidt <fschmidt@gmail.com> parents: 387 diff changeset	706 </pre></tt></p>
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	707
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	708 <p>
380 6c6c3537035e work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 373 diff changeset	709 A <i>comment</i> starts with a double hyphen (<tt>--</tt>)
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	710 anywhere outside a string.
380 6c6c3537035e work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 373 diff changeset	711 If the text immediately after <tt>--</tt> is not an opening long bracket,
6c6c3537035e work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 373 diff changeset	712 the comment is a <i>short comment</i>,
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	713 which runs until the end of the line.
380 6c6c3537035e work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 373 diff changeset	714 Otherwise, it is a <i>long comment</i>,
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	715 which runs until the corresponding closing long bracket.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	716 Long comments are frequently used to disable code temporarily.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	717
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	718
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	719
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	720
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	721
479 1285c52ea9d4 add manual heading_options Franklin Schmidt <fschmidt@gmail.com> parents: 478 diff changeset	722 <h3 <%=heading_options%> ><a name="vars">Variables</a></h3>
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	723
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	724 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	725 Variables are places that store values.
380 6c6c3537035e work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 373 diff changeset	726 There are three kinds of variables in Luan:
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	727 global variables, local variables, and table fields.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	728
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	729
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	730 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	731 A single name can denote a global variable or a local variable
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	732 (or a function's formal parameter,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	733 which is a particular kind of local variable):
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	734
389 497d4ef0a89f documentation work Franklin Schmidt <fschmidt@gmail.com> parents: 387 diff changeset	735 <p><tt><pre>
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	736 var ::= Name
389 497d4ef0a89f documentation work Franklin Schmidt <fschmidt@gmail.com> parents: 387 diff changeset	737 </pre></tt></p>
382 8557581740db added tutorial Franklin Schmidt <fschmidt@gmail.com> parents: 380 diff changeset	738
8557581740db added tutorial Franklin Schmidt <fschmidt@gmail.com> parents: 380 diff changeset	739 <p>
464 eddf7c73373b fix references in the manual Franklin Schmidt <fschmidt@gmail.com> parents: 429 diff changeset	740 Name denotes identifiers, as defined in <a href="#lex">Lexical Conventions</a>.
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	741
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	742
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	743 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	744 Any variable name is assumed to be global unless explicitly declared
464 eddf7c73373b fix references in the manual Franklin Schmidt <fschmidt@gmail.com> parents: 429 diff changeset	745 as a local (see <a href="#local_stmt">Local Declarations</a>).
380 6c6c3537035e work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 373 diff changeset	746 Local variables are <i>lexically scoped</i>:
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	747 local variables can be freely accessed by functions
464 eddf7c73373b fix references in the manual Franklin Schmidt <fschmidt@gmail.com> parents: 429 diff changeset	748 defined inside their scope (see <a href="#visibility">Visibility Rules</a>).
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	749
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	750
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	751 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	752 Before the first assignment to a variable, its value is <b>nil</b>.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	753
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	754
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	755 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	756 Square brackets are used to index a table:
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	757
389 497d4ef0a89f documentation work Franklin Schmidt <fschmidt@gmail.com> parents: 387 diff changeset	758 <p><tt><pre>
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	759 var ::= prefixexp ‘<b>[</b>’ exp ‘<b>]</b>’
389 497d4ef0a89f documentation work Franklin Schmidt <fschmidt@gmail.com> parents: 387 diff changeset	760 </pre></tt></p>
382 8557581740db added tutorial Franklin Schmidt <fschmidt@gmail.com> parents: 380 diff changeset	761
8557581740db added tutorial Franklin Schmidt <fschmidt@gmail.com> parents: 380 diff changeset	762 <p>
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	763 The meaning of accesses to table fields can be changed via metatables.
380 6c6c3537035e work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 373 diff changeset	764 An access to an indexed variable <tt>t[i]</tt> is equivalent to
6c6c3537035e work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 373 diff changeset	765 a call <tt>gettable_event(t,i)</tt>.
464 eddf7c73373b fix references in the manual Franklin Schmidt <fschmidt@gmail.com> parents: 429 diff changeset	766 (See <a href="#meta">Metatables and Metamethods</a> for a complete description of the
380 6c6c3537035e work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 373 diff changeset	767 <tt>gettable_event</tt> function.
6c6c3537035e work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 373 diff changeset	768 This function is not defined or callable in Luan.
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	769 We use it here only for explanatory purposes.)
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	770
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	771
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	772 <p>
380 6c6c3537035e work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 373 diff changeset	773 The syntax <tt>var.Name</tt> is just syntactic sugar for
6c6c3537035e work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 373 diff changeset	774 <tt>var["Name"]</tt>:
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	775
389 497d4ef0a89f documentation work Franklin Schmidt <fschmidt@gmail.com> parents: 387 diff changeset	776 <p><tt><pre>
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	777 var ::= prefixexp ‘<b>.</b>’ Name
389 497d4ef0a89f documentation work Franklin Schmidt <fschmidt@gmail.com> parents: 387 diff changeset	778 </pre></tt></p>
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	779
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	780 <p>
380 6c6c3537035e work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 373 diff changeset	781 An access to a global variable <tt>x</tt>
6c6c3537035e work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 373 diff changeset	782 is equivalent to <tt>_ENV.x</tt>.
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	783 Due to the way that chunks are compiled,
464 eddf7c73373b fix references in the manual Franklin Schmidt <fschmidt@gmail.com> parents: 429 diff changeset	784 <tt>_ENV</tt> is never a global name (see <a href="#env">Environments</a>).
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	785
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	786
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	787
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	788
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	789
479 1285c52ea9d4 add manual heading_options Franklin Schmidt <fschmidt@gmail.com> parents: 478 diff changeset	790 <h3 <%=heading_options%> ><a name="stmts">Statements</a></h3>
389 497d4ef0a89f documentation work Franklin Schmidt <fschmidt@gmail.com> parents: 387 diff changeset	791
497d4ef0a89f documentation work Franklin Schmidt <fschmidt@gmail.com> parents: 387 diff changeset	792 <p>
497d4ef0a89f documentation work Franklin Schmidt <fschmidt@gmail.com> parents: 387 diff changeset	793 Luan supports an almost conventional set of statements,
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	794 similar to those in Pascal or C.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	795 This set includes
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	796 assignments, control structures, function calls,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	797 and variable declarations.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	798
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	799
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	800
479 1285c52ea9d4 add manual heading_options Franklin Schmidt <fschmidt@gmail.com> parents: 478 diff changeset	801 <h4 <%=heading_options%> ><a name="blocks">Blocks</a></h4>
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	802
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	803 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	804 A block is a list of statements,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	805 which are executed sequentially:
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	806
389 497d4ef0a89f documentation work Franklin Schmidt <fschmidt@gmail.com> parents: 387 diff changeset	807 <p><tt><pre>
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	808 block ::= {stat}
389 497d4ef0a89f documentation work Franklin Schmidt <fschmidt@gmail.com> parents: 387 diff changeset	809 </pre></tt></p>
497d4ef0a89f documentation work Franklin Schmidt <fschmidt@gmail.com> parents: 387 diff changeset	810
497d4ef0a89f documentation work Franklin Schmidt <fschmidt@gmail.com> parents: 387 diff changeset	811 <p>
497d4ef0a89f documentation work Franklin Schmidt <fschmidt@gmail.com> parents: 387 diff changeset	812 Luan has <i>empty statements</i>
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	813 that allow you to separate statements with semicolons,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	814 start a block with a semicolon
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	815 or write two semicolons in sequence:
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	816
389 497d4ef0a89f documentation work Franklin Schmidt <fschmidt@gmail.com> parents: 387 diff changeset	817 <p><tt><pre>
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	818 stat ::= ‘<b>;</b>’
389 497d4ef0a89f documentation work Franklin Schmidt <fschmidt@gmail.com> parents: 387 diff changeset	819 </pre></tt></p>
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	820
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	821 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	822 A block can be explicitly delimited to produce a single statement:
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	823
389 497d4ef0a89f documentation work Franklin Schmidt <fschmidt@gmail.com> parents: 387 diff changeset	824 <p><tt><pre>
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	825 stat ::= <b>do</b> block <b>end</b>
389 497d4ef0a89f documentation work Franklin Schmidt <fschmidt@gmail.com> parents: 387 diff changeset	826 </pre></tt></p>
497d4ef0a89f documentation work Franklin Schmidt <fschmidt@gmail.com> parents: 387 diff changeset	827
497d4ef0a89f documentation work Franklin Schmidt <fschmidt@gmail.com> parents: 387 diff changeset	828 <p>
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	829 Explicit blocks are useful
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	830 to control the scope of variable declarations.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	831 Explicit blocks are also sometimes used to
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	832 add a <b>return</b> statement in the middle
464 eddf7c73373b fix references in the manual Franklin Schmidt <fschmidt@gmail.com> parents: 429 diff changeset	833 of another block (see <a href="#control">Control Structures</a>).
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	834
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	835
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	836
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	837
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	838
479 1285c52ea9d4 add manual heading_options Franklin Schmidt <fschmidt@gmail.com> parents: 478 diff changeset	839 <h4 <%=heading_options%> ><a name="chunks">Chunks</a></h4>
395 a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	840
a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	841 <p>
a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	842 The unit of compilation of Luan is called a <i>chunk</i>.
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	843 Syntactically,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	844 a chunk is simply a block:
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	845
395 a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	846 <p><tt><pre>
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	847 chunk ::= block
395 a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	848 </pre></tt></p>
a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	849
a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	850 <p>
a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	851 Luan handles a chunk as the body of an anonymous function
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	852 with a variable number of arguments
464 eddf7c73373b fix references in the manual Franklin Schmidt <fschmidt@gmail.com> parents: 429 diff changeset	853 (see <a href="#fn_def">Function Definitions</a>).
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	854 As such, chunks can define local variables,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	855 receive arguments, and return values.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	856
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	857
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	858 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	859 A chunk can be stored in a file or in a string inside the host program.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	860 To execute a chunk,
395 a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	861 Luan first <i>loads</i> it,
a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	862 compiling the chunk's code,
a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	863 and then Luan executes the compiled code.
a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	864
a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	865
a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	866
a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	867
a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	868
479 1285c52ea9d4 add manual heading_options Franklin Schmidt <fschmidt@gmail.com> parents: 478 diff changeset	869 <h4 <%=heading_options%> ><a name="assignment">Assignment</a></h4>
395 a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	870
a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	871 <p>
a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	872 Luan allows multiple assignments.
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	873 Therefore, the syntax for assignment
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	874 defines a list of variables on the left side
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	875 and a list of expressions on the right side.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	876 The elements in both lists are separated by commas:
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	877
395 a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	878 <p><tt><pre>
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	879 stat ::= varlist ‘<b>=</b>’ explist
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	880 varlist ::= var {‘<b>,</b>’ var}
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	881 explist ::= exp {‘<b>,</b>’ exp}
395 a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	882 </pre></tt></p>
a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	883
a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	884 <p>
464 eddf7c73373b fix references in the manual Franklin Schmidt <fschmidt@gmail.com> parents: 429 diff changeset	885 Expressions are discussed in <a href="#expressions">Expressions</a>.
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	886
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	887
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	888 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	889 Before the assignment,
395 a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	890 the list of values is <i>adjusted</i> to the length of
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	891 the list of variables.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	892 If there are more values than needed,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	893 the excess values are thrown away.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	894 If there are fewer values than needed,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	895 the list is extended with as many <b>nil</b>'s as needed.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	896 If the list of expressions ends with a function call,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	897 then all values returned by that call enter the list of values,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	898 before the adjustment
464 eddf7c73373b fix references in the manual Franklin Schmidt <fschmidt@gmail.com> parents: 429 diff changeset	899 (except when the call is enclosed in parentheses; see <a href="#expressions">Expressions</a>).
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	900
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	901
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	902 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	903 The assignment statement first evaluates all its expressions
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	904 and only then the assignments are performed.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	905 Thus the code
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	906
395 a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	907 <p><tt><pre>
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	908 i = 3
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	909 i, a[i] = i+1, 20
395 a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	910 </pre></tt></p>
a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	911
a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	912 <p>
a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	913 sets <tt>a[3]</tt> to 20, without affecting <tt>a[4]</tt>
a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	914 because the <tt>i</tt> in <tt>a[i]</tt> is evaluated (to 3)
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	915 before it is assigned 4.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	916 Similarly, the line
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	917
395 a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	918 <p><tt><pre>
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	919 x, y = y, x
395 a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	920 </pre></tt></p>
a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	921
a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	922 <p>
a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	923 exchanges the values of <tt>x</tt> and <tt>y</tt>,
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	924 and
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	925
395 a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	926 <p><tt><pre>
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	927 x, y, z = y, z, x
395 a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	928 </pre></tt></p>
a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	929
a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	930 <p>
a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	931 cyclically permutes the values of <tt>x</tt>, <tt>y</tt>, and <tt>z</tt>.
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	932
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	933
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	934 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	935 The meaning of assignments to global variables
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	936 and table fields can be changed via metatables.
395 a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	937 An assignment to an indexed variable <tt>t[i] = val</tt> is equivalent to
a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	938 <tt>settable_event(t,i,val)</tt>.
464 eddf7c73373b fix references in the manual Franklin Schmidt <fschmidt@gmail.com> parents: 429 diff changeset	939 (See <a href="#meta">Metatables and Metamethods</a> for a complete description of the
395 a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	940 <tt>settable_event</tt> function.
a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	941 This function is not defined or callable in Luan.
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	942 We use it here only for explanatory purposes.)
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	943
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	944
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	945 <p>
395 a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	946 An assignment to a global name <tt>x = val</tt>
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	947 is equivalent to the assignment
464 eddf7c73373b fix references in the manual Franklin Schmidt <fschmidt@gmail.com> parents: 429 diff changeset	948 <tt>_ENV.x = val</tt> (see <a href="#env">Environments</a>).
395 a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	949
a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	950
a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	951
a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	952
479 1285c52ea9d4 add manual heading_options Franklin Schmidt <fschmidt@gmail.com> parents: 478 diff changeset	953 <h4 <%=heading_options%> ><a name="control">Control Structures</a></h4>
395 a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	954
a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	955 <p>
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	956 The control structures
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	957 <b>if</b>, <b>while</b>, and <b>repeat</b> have the usual meaning and
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	958 familiar syntax:
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	959
395 a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	960 <p><tt><pre>
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	961 stat ::= <b>while</b> exp <b>do</b> block <b>end</b>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	962 stat ::= <b>repeat</b> block <b>until</b> exp
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	963 stat ::= <b>if</b> exp <b>then</b> block {<b>elseif</b> exp <b>then</b> block} [<b>else</b> block] <b>end</b>
395 a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	964 </pre></tt></p>
a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	965
a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	966 <p>
464 eddf7c73373b fix references in the manual Franklin Schmidt <fschmidt@gmail.com> parents: 429 diff changeset	967 Luan also has a <b>for</b> statement (see <a href="#for">For Statement</a>).
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	968
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	969
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	970 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	971 The condition expression of a
395 a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	972 control structure must be a boolean.
a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	973 Any other value type will produce an error.
a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	974 This helps catch errors and makes code more readable.
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	975
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	976
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	977 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	978 In the <b>repeat</b>–<b>until</b> loop,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	979 the inner block does not end at the <b>until</b> keyword,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	980 but only after the condition.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	981 So, the condition can refer to local variables
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	982 declared inside the loop block.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	983
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	984
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	985 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	986 The <b>break</b> statement terminates the execution of a
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	987 <b>while</b>, <b>repeat</b>, or <b>for</b> loop,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	988 skipping to the next statement after the loop:
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	989
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	990
395 a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	991 <p><tt><pre>
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	992 stat ::= <b>break</b>
395 a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	993 </pre></tt></p>
a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	994
a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	995 <p>
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	996 A <b>break</b> ends the innermost enclosing loop.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	997
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	998
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	999 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1000 The <b>return</b> statement is used to return values
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1001 from a function or a chunk
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1002 (which is an anonymous function).
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1003
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1004 Functions can return more than one value,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1005 so the syntax for the <b>return</b> statement is
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1006
395 a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	1007 <p><tt><pre>
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1008 stat ::= <b>return</b> [explist] [‘<b>;</b>’]
395 a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	1009 </pre></tt></p>
a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	1010
a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	1011
a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	1012
a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	1013
479 1285c52ea9d4 add manual heading_options Franklin Schmidt <fschmidt@gmail.com> parents: 478 diff changeset	1014 <h4 <%=heading_options%> ><a name="for">For Statement</a></h4>
395 a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	1015
a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	1016 <p>
a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	1017 The <b>for</b> statement works over functions,
a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	1018 called <i>iterators</i>.
a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	1019 On each iteration, the iterator function is called to produce a new value,
a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	1020 stopping when this new value is <b>nil</b>.
a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	1021 The <b>for</b> loop has the following syntax:
a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	1022
a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	1023 <p><tt><pre>
a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	1024 stat ::= <b>for</b> namelist <b>in</b> exp <b>do</b> block <b>end</b>
a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	1025 namelist ::= Name {‘<b>,</b>’ Name}
a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	1026 </pre></tt></p>
a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	1027
a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	1028 <p>
a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	1029 A <b>for</b> statement like
a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	1030
a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	1031 <p><tt><pre>
a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	1032 for <i>var_1</i>, ···, <i>var_n</i> in <i>exp</i> do <i>block</i> end
a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	1033 </pre></tt></p>
a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	1034
a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	1035 <p>
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1036 is equivalent to the code:
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1037
395 a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	1038 <p><tt><pre>
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1039 do
395 a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	1040 local <i>f</i> = <i>exp</i>
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1041 while true do
395 a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	1042 local <i>var_1</i>, ···, <i>var_n</i> = <i>f</i>()
a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	1043 if <i>var_1</i> == nil then break end
a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	1044 <i>block</i>
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1045 end
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1046 end
395 a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	1047 </pre></tt></p>
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1048
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1049 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1050 Note the following:
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1051
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1052 <ul>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1053
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1054 <li>
395 a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	1055 <tt><i>exp</i></tt> is evaluated only once.
a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	1056 Its result is an <i>iterator</i> function.
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1057 </li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1058
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1059 <li>
395 a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	1060 <tt><i>f</i></tt> is an invisible variable.
a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	1061 The name is here for explanatory purposes only.
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1062 </li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1063
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1064 <li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1065 You can use <b>break</b> to exit a <b>for</b> loop.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1066 </li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1067
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1068 <li>
395 a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	1069 The loop variables <tt><i>var_i</i></tt> are local to the loop;
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1070 you cannot use their values after the <b>for</b> ends.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1071 If you need these values,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1072 then assign them to other variables before breaking or exiting the loop.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1073 </li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1074
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1075 </ul>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1076
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1077
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1078
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1079
479 1285c52ea9d4 add manual heading_options Franklin Schmidt <fschmidt@gmail.com> parents: 478 diff changeset	1080 <h4 <%=heading_options%> ><a name="fn_stmt">Function Calls as Statements</a></h4>
395 a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	1081
a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	1082 <p>
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1083 To allow possible side-effects,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1084 function calls can be executed as statements:
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1085
395 a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	1086 <p><tt><pre>
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1087 stat ::= functioncall
395 a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	1088 </pre></tt></p>
a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	1089
a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	1090 <p>
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1091 In this case, all returned values are thrown away.
464 eddf7c73373b fix references in the manual Franklin Schmidt <fschmidt@gmail.com> parents: 429 diff changeset	1092 Function calls are explained in <a href="#fn_calls">Function Calls</a>.
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1093
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1094
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1095
479 1285c52ea9d4 add manual heading_options Franklin Schmidt <fschmidt@gmail.com> parents: 478 diff changeset	1096 <h4 <%=heading_options%> ><a name="local_stmt">Local Declarations</a></h4>
395 a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	1097
a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	1098 <p>
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1099 Local variables can be declared anywhere inside a block.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1100 The declaration can include an initial assignment:
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1101
395 a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	1102 <p><tt><pre>
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1103 stat ::= <b>local</b> namelist [‘<b>=</b>’ explist]
395 a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	1104 </pre></tt></p>
a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	1105
a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	1106 <p>
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1107 If present, an initial assignment has the same semantics
464 eddf7c73373b fix references in the manual Franklin Schmidt <fschmidt@gmail.com> parents: 429 diff changeset	1108 of a multiple assignment (see <a href="#assignment">Assignment</a>).
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1109 Otherwise, all variables are initialized with <b>nil</b>.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1110
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1111
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1112 <p>
464 eddf7c73373b fix references in the manual Franklin Schmidt <fschmidt@gmail.com> parents: 429 diff changeset	1113 A chunk is also a block (see <a href="#chunks">Chunks</a>),
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1114 and so local variables can be declared in a chunk outside any explicit block.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1115
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1116
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1117 <p>
464 eddf7c73373b fix references in the manual Franklin Schmidt <fschmidt@gmail.com> parents: 429 diff changeset	1118 The visibility rules for local variables are explained in <a href="#visibility">Visibility Rules</a>.
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1119
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1120
479 1285c52ea9d4 add manual heading_options Franklin Schmidt <fschmidt@gmail.com> parents: 478 diff changeset	1121 <h4 <%=heading_options%> ><a name="template_stmt">Template Statements</a></h4>
465 47c7de1f2322 documentation work Franklin Schmidt <fschmidt@gmail.com> parents: 464 diff changeset	1122
47c7de1f2322 documentation work Franklin Schmidt <fschmidt@gmail.com> parents: 464 diff changeset	1123 <p>Template statements are based on <a href="#template_expr">template exressions</a> and provide the full equivalent of <a href="http://en.wikipedia.org/wiki/JavaServer_Pages">JSP</a> but in a general way. Template statements write the equivalent template exression to standard output. For example:</p>
47c7de1f2322 documentation work Franklin Schmidt <fschmidt@gmail.com> parents: 464 diff changeset	1124
47c7de1f2322 documentation work Franklin Schmidt <fschmidt@gmail.com> parents: 464 diff changeset	1125 <p><tt><pre><%=Html.encode[[
47c7de1f2322 documentation work Franklin Schmidt <fschmidt@gmail.com> parents: 464 diff changeset	1126 local name = "Bob"
47c7de1f2322 documentation work Franklin Schmidt <fschmidt@gmail.com> parents: 464 diff changeset	1127 %>
469 85467f95ab13 minor Franklin Schmidt <fschmidt@gmail.com> parents: 468 diff changeset	1128 Hello <%= name %>!
85467f95ab13 minor Franklin Schmidt <fschmidt@gmail.com> parents: 468 diff changeset	1129 Bye <%= name %>.
465 47c7de1f2322 documentation work Franklin Schmidt <fschmidt@gmail.com> parents: 464 diff changeset	1130 <%
47c7de1f2322 documentation work Franklin Schmidt <fschmidt@gmail.com> parents: 464 diff changeset	1131 ]]%></pre></tt></p>
47c7de1f2322 documentation work Franklin Schmidt <fschmidt@gmail.com> parents: 464 diff changeset	1132
47c7de1f2322 documentation work Franklin Schmidt <fschmidt@gmail.com> parents: 464 diff changeset	1133 <p>is equivalent to the code:</p>
47c7de1f2322 documentation work Franklin Schmidt <fschmidt@gmail.com> parents: 464 diff changeset	1134
47c7de1f2322 documentation work Franklin Schmidt <fschmidt@gmail.com> parents: 464 diff changeset	1135 <p><tt><pre><%=Html.encode[[
47c7de1f2322 documentation work Franklin Schmidt <fschmidt@gmail.com> parents: 464 diff changeset	1136 local name = "Bob"
47c7de1f2322 documentation work Franklin Schmidt <fschmidt@gmail.com> parents: 464 diff changeset	1137 require("luan:Io").stdout.write( %>
469 85467f95ab13 minor Franklin Schmidt <fschmidt@gmail.com> parents: 468 diff changeset	1138 Hello <%= name %>!
85467f95ab13 minor Franklin Schmidt <fschmidt@gmail.com> parents: 468 diff changeset	1139 Bye <%= name %>.
465 47c7de1f2322 documentation work Franklin Schmidt <fschmidt@gmail.com> parents: 464 diff changeset	1140 <% )
47c7de1f2322 documentation work Franklin Schmidt <fschmidt@gmail.com> parents: 464 diff changeset	1141 ]]%></pre></tt></p>
47c7de1f2322 documentation work Franklin Schmidt <fschmidt@gmail.com> parents: 464 diff changeset	1142
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1143
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1144
479 1285c52ea9d4 add manual heading_options Franklin Schmidt <fschmidt@gmail.com> parents: 478 diff changeset	1145 <h3 <%=heading_options%> ><a name="expressions">Expressions</a></h3>
395 a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	1146
a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	1147 <p>
a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	1148 The basic expressions in Luan are the following:
a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	1149
a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	1150 <p><tt><pre>
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1151 exp ::= prefixexp
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1152 exp ::= <b>nil</b> \| <b>false</b> \| <b>true</b>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1153 exp ::= Numeral
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1154 exp ::= LiteralString
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1155 exp ::= functiondef
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1156 exp ::= tableconstructor
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1157 exp ::= ‘<b>...</b>’
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1158 exp ::= exp binop exp
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1159 exp ::= unop exp
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1160 prefixexp ::= var \| functioncall \| ‘<b>(</b>’ exp ‘<b>)</b>’
395 a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	1161 </pre></tt></p>
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1162
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1163 <p>
464 eddf7c73373b fix references in the manual Franklin Schmidt <fschmidt@gmail.com> parents: 429 diff changeset	1164 Numerals and literal strings are explained in <a href="#lex">Lexical Conventions</a>;
eddf7c73373b fix references in the manual Franklin Schmidt <fschmidt@gmail.com> parents: 429 diff changeset	1165 variables are explained in <a href="#vars">Variables</a>;
eddf7c73373b fix references in the manual Franklin Schmidt <fschmidt@gmail.com> parents: 429 diff changeset	1166 function definitions are explained in <a href="#fn_def">Function Definitions</a>;
eddf7c73373b fix references in the manual Franklin Schmidt <fschmidt@gmail.com> parents: 429 diff changeset	1167 function calls are explained in <a href="#fn_calls">Function Calls</a>;
eddf7c73373b fix references in the manual Franklin Schmidt <fschmidt@gmail.com> parents: 429 diff changeset	1168 table constructors are explained in <a href="#constructors">Table Constructors</a>.
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1169 Vararg expressions,
395 a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	1170 denoted by three dots ('<tt>...</tt>'), can only be used when
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1171 directly inside a vararg function;
464 eddf7c73373b fix references in the manual Franklin Schmidt <fschmidt@gmail.com> parents: 429 diff changeset	1172 they are explained in <a href="#fn_def">Function Definitions</a>.
eddf7c73373b fix references in the manual Franklin Schmidt <fschmidt@gmail.com> parents: 429 diff changeset	1173
eddf7c73373b fix references in the manual Franklin Schmidt <fschmidt@gmail.com> parents: 429 diff changeset	1174
eddf7c73373b fix references in the manual Franklin Schmidt <fschmidt@gmail.com> parents: 429 diff changeset	1175 <p>
eddf7c73373b fix references in the manual Franklin Schmidt <fschmidt@gmail.com> parents: 429 diff changeset	1176 Binary operators comprise arithmetic operators (see <a href="#arithmetic">Arithmetic Operators</a>),
eddf7c73373b fix references in the manual Franklin Schmidt <fschmidt@gmail.com> parents: 429 diff changeset	1177 relational operators (see <a href="#relational">Relational Operators</a>), logical operators (see <a href="#logical_ops">Logical Operators</a>),
eddf7c73373b fix references in the manual Franklin Schmidt <fschmidt@gmail.com> parents: 429 diff changeset	1178 and the concatenation operator (see <a href="#concatenation">Concatenation</a>).
eddf7c73373b fix references in the manual Franklin Schmidt <fschmidt@gmail.com> parents: 429 diff changeset	1179 Unary operators comprise the unary minus (see <a href="#arithmetic">Arithmetic Operators</a>),
eddf7c73373b fix references in the manual Franklin Schmidt <fschmidt@gmail.com> parents: 429 diff changeset	1180 the unary logical <b>not</b> (see <a href="#logical_ops">Logical Operators</a>),
eddf7c73373b fix references in the manual Franklin Schmidt <fschmidt@gmail.com> parents: 429 diff changeset	1181 and the unary <em>length operator</em> (see <a href="#length">The Length Operator</a>).
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1182
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1183
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1184 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1185 Both function calls and vararg expressions can result in multiple values.
464 eddf7c73373b fix references in the manual Franklin Schmidt <fschmidt@gmail.com> parents: 429 diff changeset	1186 If a function call is used as a statement (see <a href="#fn_stmt">Function Calls as Statements</a>),
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1187 then its return list is adjusted to zero elements,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1188 thus discarding all returned values.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1189 If an expression is used as the last (or the only) element
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1190 of a list of expressions,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1191 then no adjustment is made
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1192 (unless the expression is enclosed in parentheses).
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1193 In all other contexts,
395 a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	1194 Luan adjusts the result list to one element,
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1195 either discarding all values except the first one
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1196 or adding a single <b>nil</b> if there are no values.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1197
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1198
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1199 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1200 Here are some examples:
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1201
395 a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	1202 <p><tt><pre>
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1203 f() -- adjusted to 0 results
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1204 g(f(), x) -- f() is adjusted to 1 result
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1205 g(x, f()) -- g gets x plus all results from f()
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1206 a,b,c = f(), x -- f() is adjusted to 1 result (c gets nil)
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1207 a,b = ... -- a gets the first vararg parameter, b gets
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1208 -- the second (both a and b can get nil if there
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1209 -- is no corresponding vararg parameter)
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1210
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1211 a,b,c = x, f() -- f() is adjusted to 2 results
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1212 a,b,c = f() -- f() is adjusted to 3 results
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1213 return f() -- returns all results from f()
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1214 return ... -- returns all received vararg parameters
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1215 return x,y,f() -- returns x, y, and all results from f()
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1216 {f()} -- creates a list with all results from f()
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1217 {...} -- creates a list with all vararg parameters
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1218 {f(), nil} -- f() is adjusted to 1 result
395 a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	1219 </pre></tt></p>
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1220
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1221 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1222 Any expression enclosed in parentheses always results in only one value.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1223 Thus,
395 a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	1224 <tt>(f(x,y,z))</tt> is always a single value,
a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	1225 even if <tt>f</tt> returns several values.
a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	1226 (The value of <tt>(f(x,y,z))</tt> is the first value returned by <tt>f</tt>
a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	1227 or <b>nil</b> if <tt>f</tt> does not return any values.)
a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	1228
a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	1229
a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	1230
479 1285c52ea9d4 add manual heading_options Franklin Schmidt <fschmidt@gmail.com> parents: 478 diff changeset	1231 <h4 <%=heading_options%> ><a name="arithmetic">Arithmetic Operators</a></h4>
395 a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	1232
a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	1233 <p>
a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	1234 Luan supports the following arithmetic operators:
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1235
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1236 <ul>
395 a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	1237 <li><b><tt>+</tt>: </b>addition</li>
a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	1238 <li><b><tt>-</tt>: </b>subtraction</li>
a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	1239 <li><b><tt>*</tt>: </b>multiplication</li>
a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	1240 <li><b><tt>/</tt>: </b>division</li>
a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	1241 <li><b><tt>%</tt>: </b>modulo</li>
a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	1242 <li><b><tt>^</tt>: </b>exponentiation</li>
a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	1243 <li><b><tt>-</tt>: </b>unary minus</li>
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1244 </ul>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1245
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1246 <p>
395 a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	1247 Addition, subtraction, multiplication, division, and unary minus are the same as these operators in Java. Exponentiation uses Java's <a href="http://docs.oracle.com/javase/7/docs/api/java/lang/Math.html#pow(double,%20double)">Math.pow</a> function.
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1248
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1249 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1250 Modulo is defined as the remainder of a division
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1251 that rounds the quotient towards minus infinite (floor division).
395 a7cb58532846 work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 391 diff changeset	1252 (The Java modulo operator is not used.)
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1253
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1254
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1255
479 1285c52ea9d4 add manual heading_options Franklin Schmidt <fschmidt@gmail.com> parents: 478 diff changeset	1256 <h4 <%=heading_options%> ><a name="conversions">Coercions and Conversions</a></h4>
396 ba8b0aae6453 work on manual; Franklin Schmidt <fschmidt@gmail.com> parents: 395 diff changeset	1257
ba8b0aae6453 work on manual; Franklin Schmidt <fschmidt@gmail.com> parents: 395 diff changeset	1258 <p>
465 47c7de1f2322 documentation work Franklin Schmidt <fschmidt@gmail.com> parents: 464 diff changeset	1259 Luan generally avoids automatic conversions.
47c7de1f2322 documentation work Franklin Schmidt <fschmidt@gmail.com> parents: 464 diff changeset	1260 String concatenation automatically converts all of its arguments to strings.
47c7de1f2322 documentation work Franklin Schmidt <fschmidt@gmail.com> parents: 464 diff changeset	1261
47c7de1f2322 documentation work Franklin Schmidt <fschmidt@gmail.com> parents: 464 diff changeset	1262 <p>
47c7de1f2322 documentation work Franklin Schmidt <fschmidt@gmail.com> parents: 464 diff changeset	1263 Luan provides library functions for explicit type conversions.
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1264
396 ba8b0aae6453 work on manual; Franklin Schmidt <fschmidt@gmail.com> parents: 395 diff changeset	1265
ba8b0aae6453 work on manual; Franklin Schmidt <fschmidt@gmail.com> parents: 395 diff changeset	1266
ba8b0aae6453 work on manual; Franklin Schmidt <fschmidt@gmail.com> parents: 395 diff changeset	1267
479 1285c52ea9d4 add manual heading_options Franklin Schmidt <fschmidt@gmail.com> parents: 478 diff changeset	1268 <h4 <%=heading_options%> ><a name="relational">Relational Operators</a></h4>
396 ba8b0aae6453 work on manual; Franklin Schmidt <fschmidt@gmail.com> parents: 395 diff changeset	1269
ba8b0aae6453 work on manual; Franklin Schmidt <fschmidt@gmail.com> parents: 395 diff changeset	1270 <p>
ba8b0aae6453 work on manual; Franklin Schmidt <fschmidt@gmail.com> parents: 395 diff changeset	1271 Luan supports the following relational operators:
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1272
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1273 <ul>
396 ba8b0aae6453 work on manual; Franklin Schmidt <fschmidt@gmail.com> parents: 395 diff changeset	1274 <li><b><tt>==</tt>: </b>equality</li>
ba8b0aae6453 work on manual; Franklin Schmidt <fschmidt@gmail.com> parents: 395 diff changeset	1275 <li><b><tt>~=</tt>: </b>inequality</li>
ba8b0aae6453 work on manual; Franklin Schmidt <fschmidt@gmail.com> parents: 395 diff changeset	1276 <li><b><tt><</tt>: </b>less than</li>
ba8b0aae6453 work on manual; Franklin Schmidt <fschmidt@gmail.com> parents: 395 diff changeset	1277 <li><b><tt>></tt>: </b>greater than</li>
ba8b0aae6453 work on manual; Franklin Schmidt <fschmidt@gmail.com> parents: 395 diff changeset	1278 <li><b><tt><=</tt>: </b>less or equal</li>
ba8b0aae6453 work on manual; Franklin Schmidt <fschmidt@gmail.com> parents: 395 diff changeset	1279 <li><b><tt>>=</tt>: </b>greater or equal</li>
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1280 </ul><p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1281 These operators always result in <b>false</b> or <b>true</b>.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1282
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1283
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1284 <p>
396 ba8b0aae6453 work on manual; Franklin Schmidt <fschmidt@gmail.com> parents: 395 diff changeset	1285 Equality (<tt>==</tt>) first compares the type of its operands.
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1286 If the types are different, then the result is <b>false</b>.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1287 Otherwise, the values of the operands are compared.
396 ba8b0aae6453 work on manual; Franklin Schmidt <fschmidt@gmail.com> parents: 395 diff changeset	1288 Strings, numbers, and binary values are compared in the obvious way (by value).
ba8b0aae6453 work on manual; Franklin Schmidt <fschmidt@gmail.com> parents: 395 diff changeset	1289
ba8b0aae6453 work on manual; Franklin Schmidt <fschmidt@gmail.com> parents: 395 diff changeset	1290 <p>
ba8b0aae6453 work on manual; Franklin Schmidt <fschmidt@gmail.com> parents: 395 diff changeset	1291 Tables
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1292 are compared by reference:
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1293 two objects are considered equal only if they are the same object.
396 ba8b0aae6453 work on manual; Franklin Schmidt <fschmidt@gmail.com> parents: 395 diff changeset	1294 Every time you create a new table,
ba8b0aae6453 work on manual; Franklin Schmidt <fschmidt@gmail.com> parents: 395 diff changeset	1295 it is different from any previously existing table.
ba8b0aae6453 work on manual; Franklin Schmidt <fschmidt@gmail.com> parents: 395 diff changeset	1296 Closures are also compared by reference.
ba8b0aae6453 work on manual; Franklin Schmidt <fschmidt@gmail.com> parents: 395 diff changeset	1297
ba8b0aae6453 work on manual; Franklin Schmidt <fschmidt@gmail.com> parents: 395 diff changeset	1298 <p>
417 a40e99cf0b0b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 396 diff changeset	1299 You can change the way that Luan compares tables
464 eddf7c73373b fix references in the manual Franklin Schmidt <fschmidt@gmail.com> parents: 429 diff changeset	1300 by using the "eq" metamethod (see <a href="#meta">Metatables and Metamethods</a>).
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1301
396 ba8b0aae6453 work on manual; Franklin Schmidt <fschmidt@gmail.com> parents: 395 diff changeset	1302 <p>
ba8b0aae6453 work on manual; Franklin Schmidt <fschmidt@gmail.com> parents: 395 diff changeset	1303 Userdata are Java objects. They are compared for equality with the Java <a href="http://docs.oracle.com/javase/7/docs/api/java/lang/Object.html#equals(java.lang.Object)"><tt>equals</tt></a> method.
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1304
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1305 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1306 Equality comparisons do not convert strings to numbers
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1307 or vice versa.
396 ba8b0aae6453 work on manual; Franklin Schmidt <fschmidt@gmail.com> parents: 395 diff changeset	1308 Thus, <tt>"0"==0</tt> evaluates to <b>false</b>,
ba8b0aae6453 work on manual; Franklin Schmidt <fschmidt@gmail.com> parents: 395 diff changeset	1309 and <tt>t[0]</tt> and <tt>t["0"]</tt> denote different
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1310 entries in a table.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1311
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1312
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1313 <p>
396 ba8b0aae6453 work on manual; Franklin Schmidt <fschmidt@gmail.com> parents: 395 diff changeset	1314 The operator <tt>~=</tt> is exactly the negation of equality (<tt>==</tt>).
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1315
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1316
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1317 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1318 The order operators work as follows.
396 ba8b0aae6453 work on manual; Franklin Schmidt <fschmidt@gmail.com> parents: 395 diff changeset	1319
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1320 If both arguments are numbers,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1321 then they are compared following
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1322 the usual rule for binary operations.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1323 Otherwise, if both arguments are strings,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1324 then their values are compared according to the current locale.
396 ba8b0aae6453 work on manual; Franklin Schmidt <fschmidt@gmail.com> parents: 395 diff changeset	1325 Otherwise, Luan tries to call the "lt" or the "le"
464 eddf7c73373b fix references in the manual Franklin Schmidt <fschmidt@gmail.com> parents: 429 diff changeset	1326 metamethod (see <a href="#meta">Metatables and Metamethods</a>).
396 ba8b0aae6453 work on manual; Franklin Schmidt <fschmidt@gmail.com> parents: 395 diff changeset	1327 A comparison <tt>a > b</tt> is translated to <tt>b < a</tt>
ba8b0aae6453 work on manual; Franklin Schmidt <fschmidt@gmail.com> parents: 395 diff changeset	1328 and <tt>a >= b</tt> is translated to <tt>b <= a</tt>.
ba8b0aae6453 work on manual; Franklin Schmidt <fschmidt@gmail.com> parents: 395 diff changeset	1329
ba8b0aae6453 work on manual; Franklin Schmidt <fschmidt@gmail.com> parents: 395 diff changeset	1330
ba8b0aae6453 work on manual; Franklin Schmidt <fschmidt@gmail.com> parents: 395 diff changeset	1331
ba8b0aae6453 work on manual; Franklin Schmidt <fschmidt@gmail.com> parents: 395 diff changeset	1332
ba8b0aae6453 work on manual; Franklin Schmidt <fschmidt@gmail.com> parents: 395 diff changeset	1333
479 1285c52ea9d4 add manual heading_options Franklin Schmidt <fschmidt@gmail.com> parents: 478 diff changeset	1334 <h4 <%=heading_options%> ><a name="logical_ops">Logical Operators</a></h4>
396 ba8b0aae6453 work on manual; Franklin Schmidt <fschmidt@gmail.com> parents: 395 diff changeset	1335
ba8b0aae6453 work on manual; Franklin Schmidt <fschmidt@gmail.com> parents: 395 diff changeset	1336 <p>
ba8b0aae6453 work on manual; Franklin Schmidt <fschmidt@gmail.com> parents: 395 diff changeset	1337 The logical operators in Luan are
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1338 <b>and</b>, <b>or</b>, and <b>not</b>.
396 ba8b0aae6453 work on manual; Franklin Schmidt <fschmidt@gmail.com> parents: 395 diff changeset	1339 The <b>and</b> and <b>or</b> operators consider both <b>false</b> and <b>nil</b> as false
ba8b0aae6453 work on manual; Franklin Schmidt <fschmidt@gmail.com> parents: 395 diff changeset	1340 and anything else as true.
464 eddf7c73373b fix references in the manual Franklin Schmidt <fschmidt@gmail.com> parents: 429 diff changeset	1341 Like the control structures (see <a href="#control">Control Structures</a>),
396 ba8b0aae6453 work on manual; Franklin Schmidt <fschmidt@gmail.com> parents: 395 diff changeset	1342 the <b>not</b> operator requires a boolean value.
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1343
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1344 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1345 The negation operator <b>not</b> always returns <b>false</b> or <b>true</b>.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1346 The conjunction operator <b>and</b> returns its first argument
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1347 if this value is <b>false</b> or <b>nil</b>;
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1348 otherwise, <b>and</b> returns its second argument.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1349 The disjunction operator <b>or</b> returns its first argument
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1350 if this value is different from <b>nil</b> and <b>false</b>;
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1351 otherwise, <b>or</b> returns its second argument.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1352 Both <b>and</b> and <b>or</b> use short-circuit evaluation;
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1353 that is,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1354 the second operand is evaluated only if necessary.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1355 Here are some examples:
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1356
396 ba8b0aae6453 work on manual; Franklin Schmidt <fschmidt@gmail.com> parents: 395 diff changeset	1357 <p><tt><pre>
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1358 10 or 20 --> 10
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1359 10 or error() --> 10
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1360 nil or "a" --> "a"
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1361 nil and 10 --> nil
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1362 false and error() --> false
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1363 false and nil --> false
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1364 false or nil --> nil
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1365 10 and 20 --> 20
396 ba8b0aae6453 work on manual; Franklin Schmidt <fschmidt@gmail.com> parents: 395 diff changeset	1366 </pre></tt></p>
ba8b0aae6453 work on manual; Franklin Schmidt <fschmidt@gmail.com> parents: 395 diff changeset	1367
ba8b0aae6453 work on manual; Franklin Schmidt <fschmidt@gmail.com> parents: 395 diff changeset	1368 <p>
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1369 (In this manual,
396 ba8b0aae6453 work on manual; Franklin Schmidt <fschmidt@gmail.com> parents: 395 diff changeset	1370 <tt>--></tt> indicates the result of the preceding expression.)
ba8b0aae6453 work on manual; Franklin Schmidt <fschmidt@gmail.com> parents: 395 diff changeset	1371
ba8b0aae6453 work on manual; Franklin Schmidt <fschmidt@gmail.com> parents: 395 diff changeset	1372
ba8b0aae6453 work on manual; Franklin Schmidt <fschmidt@gmail.com> parents: 395 diff changeset	1373
479 1285c52ea9d4 add manual heading_options Franklin Schmidt <fschmidt@gmail.com> parents: 478 diff changeset	1374 <h4 <%=heading_options%> ><a name="concatenation">Concatenation</a></h4>
396 ba8b0aae6453 work on manual; Franklin Schmidt <fschmidt@gmail.com> parents: 395 diff changeset	1375
ba8b0aae6453 work on manual; Franklin Schmidt <fschmidt@gmail.com> parents: 395 diff changeset	1376 <p>
ba8b0aae6453 work on manual; Franklin Schmidt <fschmidt@gmail.com> parents: 395 diff changeset	1377 The string concatenation operator in Luan is
ba8b0aae6453 work on manual; Franklin Schmidt <fschmidt@gmail.com> parents: 395 diff changeset	1378 denoted by two dots ('<tt>..</tt>').
ba8b0aae6453 work on manual; Franklin Schmidt <fschmidt@gmail.com> parents: 395 diff changeset	1379 All operands are converted to strings.
ba8b0aae6453 work on manual; Franklin Schmidt <fschmidt@gmail.com> parents: 395 diff changeset	1380
ba8b0aae6453 work on manual; Franklin Schmidt <fschmidt@gmail.com> parents: 395 diff changeset	1381
ba8b0aae6453 work on manual; Franklin Schmidt <fschmidt@gmail.com> parents: 395 diff changeset	1382
479 1285c52ea9d4 add manual heading_options Franklin Schmidt <fschmidt@gmail.com> parents: 478 diff changeset	1383 <h4 <%=heading_options%> ><a name="length">The Length Operator</a></h4>
396 ba8b0aae6453 work on manual; Franklin Schmidt <fschmidt@gmail.com> parents: 395 diff changeset	1384
ba8b0aae6453 work on manual; Franklin Schmidt <fschmidt@gmail.com> parents: 395 diff changeset	1385 <p>
ba8b0aae6453 work on manual; Franklin Schmidt <fschmidt@gmail.com> parents: 395 diff changeset	1386 The length operator is denoted by the unary prefix operator <tt>#</tt>.
ba8b0aae6453 work on manual; Franklin Schmidt <fschmidt@gmail.com> parents: 395 diff changeset	1387 The length of a string is its number of characters.
ba8b0aae6453 work on manual; Franklin Schmidt <fschmidt@gmail.com> parents: 395 diff changeset	1388 The length of a binary is its number of bytes.
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1389
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1390
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1391 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1392 A program can modify the behavior of the length operator for
464 eddf7c73373b fix references in the manual Franklin Schmidt <fschmidt@gmail.com> parents: 429 diff changeset	1393 any table through the <tt>__len</tt> metamethod (see <a href="#meta">Metatables and Metamethods</a>).
396 ba8b0aae6453 work on manual; Franklin Schmidt <fschmidt@gmail.com> parents: 395 diff changeset	1394
ba8b0aae6453 work on manual; Franklin Schmidt <fschmidt@gmail.com> parents: 395 diff changeset	1395
ba8b0aae6453 work on manual; Franklin Schmidt <fschmidt@gmail.com> parents: 395 diff changeset	1396 <p>
ba8b0aae6453 work on manual; Franklin Schmidt <fschmidt@gmail.com> parents: 395 diff changeset	1397 Unless a <tt>__len</tt> metamethod is given,
ba8b0aae6453 work on manual; Franklin Schmidt <fschmidt@gmail.com> parents: 395 diff changeset	1398 the length of a table <tt>t</tt> is defined
ba8b0aae6453 work on manual; Franklin Schmidt <fschmidt@gmail.com> parents: 395 diff changeset	1399 as the number of elements in <em>sequence</em>,
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1400 that is,
396 ba8b0aae6453 work on manual; Franklin Schmidt <fschmidt@gmail.com> parents: 395 diff changeset	1401 the size of the set of its positive numeric keys is equal to <em>{1..n}</em>
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1402 for some non-negative integer <em>n</em>.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1403 In that case, <em>n</em> is its length.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1404 Note that a table like
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1405
396 ba8b0aae6453 work on manual; Franklin Schmidt <fschmidt@gmail.com> parents: 395 diff changeset	1406 <p><tt><pre>
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1407 {10, 20, nil, 40}
396 ba8b0aae6453 work on manual; Franklin Schmidt <fschmidt@gmail.com> parents: 395 diff changeset	1408 </pre></tt></p>
ba8b0aae6453 work on manual; Franklin Schmidt <fschmidt@gmail.com> parents: 395 diff changeset	1409
ba8b0aae6453 work on manual; Franklin Schmidt <fschmidt@gmail.com> parents: 395 diff changeset	1410 <p>
ba8b0aae6453 work on manual; Franklin Schmidt <fschmidt@gmail.com> parents: 395 diff changeset	1411 has a length of <tt>2</tt>, because that is the last key in sequence.
ba8b0aae6453 work on manual; Franklin Schmidt <fschmidt@gmail.com> parents: 395 diff changeset	1412
ba8b0aae6453 work on manual; Franklin Schmidt <fschmidt@gmail.com> parents: 395 diff changeset	1413
ba8b0aae6453 work on manual; Franklin Schmidt <fschmidt@gmail.com> parents: 395 diff changeset	1414
ba8b0aae6453 work on manual; Franklin Schmidt <fschmidt@gmail.com> parents: 395 diff changeset	1415
ba8b0aae6453 work on manual; Franklin Schmidt <fschmidt@gmail.com> parents: 395 diff changeset	1416
479 1285c52ea9d4 add manual heading_options Franklin Schmidt <fschmidt@gmail.com> parents: 478 diff changeset	1417 <h4 <%=heading_options%> ><a name="precedence">Precedence</a></h4>
396 ba8b0aae6453 work on manual; Franklin Schmidt <fschmidt@gmail.com> parents: 395 diff changeset	1418
ba8b0aae6453 work on manual; Franklin Schmidt <fschmidt@gmail.com> parents: 395 diff changeset	1419 <p>
ba8b0aae6453 work on manual; Franklin Schmidt <fschmidt@gmail.com> parents: 395 diff changeset	1420 Operator precedence in Luan follows the table below,
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1421 from lower to higher priority:
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1422
396 ba8b0aae6453 work on manual; Franklin Schmidt <fschmidt@gmail.com> parents: 395 diff changeset	1423 <p><tt><pre>
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1424 or
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1425 and
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1426 < > <= >= ~= ==
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1427 ..
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1428 + -
396 ba8b0aae6453 work on manual; Franklin Schmidt <fschmidt@gmail.com> parents: 395 diff changeset	1429 * / %
ba8b0aae6453 work on manual; Franklin Schmidt <fschmidt@gmail.com> parents: 395 diff changeset	1430 unary operators (not # -)
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1431 ^
396 ba8b0aae6453 work on manual; Franklin Schmidt <fschmidt@gmail.com> parents: 395 diff changeset	1432 </pre></tt></p>
ba8b0aae6453 work on manual; Franklin Schmidt <fschmidt@gmail.com> parents: 395 diff changeset	1433
ba8b0aae6453 work on manual; Franklin Schmidt <fschmidt@gmail.com> parents: 395 diff changeset	1434 <p>
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1435 As usual,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1436 you can use parentheses to change the precedences of an expression.
396 ba8b0aae6453 work on manual; Franklin Schmidt <fschmidt@gmail.com> parents: 395 diff changeset	1437 The concatenation ('<tt>..</tt>') and exponentiation ('<tt>^</tt>')
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1438 operators are right associative.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1439 All other binary operators are left associative.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1440
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1441
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1442
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1443
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1444
479 1285c52ea9d4 add manual heading_options Franklin Schmidt <fschmidt@gmail.com> parents: 478 diff changeset	1445 <h4 <%=heading_options%> ><a name="constructors">Table Constructors</a></h4>
396 ba8b0aae6453 work on manual; Franklin Schmidt <fschmidt@gmail.com> parents: 395 diff changeset	1446
ba8b0aae6453 work on manual; Franklin Schmidt <fschmidt@gmail.com> parents: 395 diff changeset	1447 <p>
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1448 Table constructors are expressions that create tables.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1449 Every time a constructor is evaluated, a new table is created.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1450 A constructor can be used to create an empty table
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1451 or to create a table and initialize some of its fields.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1452 The general syntax for constructors is
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1453
396 ba8b0aae6453 work on manual; Franklin Schmidt <fschmidt@gmail.com> parents: 395 diff changeset	1454 <p><tt><pre>
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1455 tableconstructor ::= ‘<b>{</b>’ [fieldlist] ‘<b>}</b>’
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1456 fieldlist ::= field {fieldsep field} [fieldsep]
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1457 field ::= ‘<b>[</b>’ exp ‘<b>]</b>’ ‘<b>=</b>’ exp \| Name ‘<b>=</b>’ exp \| exp
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1458 fieldsep ::= ‘<b>,</b>’ \| ‘<b>;</b>’
396 ba8b0aae6453 work on manual; Franklin Schmidt <fschmidt@gmail.com> parents: 395 diff changeset	1459 </pre></tt></p>
ba8b0aae6453 work on manual; Franklin Schmidt <fschmidt@gmail.com> parents: 395 diff changeset	1460
ba8b0aae6453 work on manual; Franklin Schmidt <fschmidt@gmail.com> parents: 395 diff changeset	1461 <p>
ba8b0aae6453 work on manual; Franklin Schmidt <fschmidt@gmail.com> parents: 395 diff changeset	1462 Each field of the form <tt>[exp1] = exp2</tt> adds to the new table an entry
ba8b0aae6453 work on manual; Franklin Schmidt <fschmidt@gmail.com> parents: 395 diff changeset	1463 with key <tt>exp1</tt> and value <tt>exp2</tt>.
ba8b0aae6453 work on manual; Franklin Schmidt <fschmidt@gmail.com> parents: 395 diff changeset	1464 A field of the form <tt>name = exp</tt> is equivalent to
ba8b0aae6453 work on manual; Franklin Schmidt <fschmidt@gmail.com> parents: 395 diff changeset	1465 <tt>["name"] = exp</tt>.
ba8b0aae6453 work on manual; Franklin Schmidt <fschmidt@gmail.com> parents: 395 diff changeset	1466 Finally, fields of the form <tt>exp</tt> are equivalent to
ba8b0aae6453 work on manual; Franklin Schmidt <fschmidt@gmail.com> parents: 395 diff changeset	1467 <tt>[i] = exp</tt>, where <tt>i</tt> are consecutive integers
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1468 starting with 1.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1469 Fields in the other formats do not affect this counting.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1470 For example,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1471
396 ba8b0aae6453 work on manual; Franklin Schmidt <fschmidt@gmail.com> parents: 395 diff changeset	1472 <p><tt><pre>
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1473 a = { [f(1)] = g; "x", "y"; x = 1, f(x), [30] = 23; 45 }
396 ba8b0aae6453 work on manual; Franklin Schmidt <fschmidt@gmail.com> parents: 395 diff changeset	1474 </pre></tt></p>
ba8b0aae6453 work on manual; Franklin Schmidt <fschmidt@gmail.com> parents: 395 diff changeset	1475
ba8b0aae6453 work on manual; Franklin Schmidt <fschmidt@gmail.com> parents: 395 diff changeset	1476 <p>
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1477 is equivalent to
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1478
396 ba8b0aae6453 work on manual; Franklin Schmidt <fschmidt@gmail.com> parents: 395 diff changeset	1479 <p><tt><pre>
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1480 do
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1481 local t = {}
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1482 t[f(1)] = g
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1483 t[1] = "x" -- 1st exp
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1484 t[2] = "y" -- 2nd exp
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1485 t.x = 1 -- t["x"] = 1
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1486 t[3] = f(x) -- 3rd exp
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1487 t[30] = 23
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1488 t[4] = 45 -- 4th exp
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1489 a = t
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1490 end
396 ba8b0aae6453 work on manual; Franklin Schmidt <fschmidt@gmail.com> parents: 395 diff changeset	1491 </pre></tt></p>
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1492
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1493 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1494 The order of the assignments in a constructor is undefined.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1495 (This order would be relevant only when there are repeated keys.)
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1496
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1497
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1498 <p>
396 ba8b0aae6453 work on manual; Franklin Schmidt <fschmidt@gmail.com> parents: 395 diff changeset	1499 If the last field in the list has the form <tt>exp</tt>
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1500 and the expression is a function call or a vararg expression,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1501 then all values returned by this expression enter the list consecutively
464 eddf7c73373b fix references in the manual Franklin Schmidt <fschmidt@gmail.com> parents: 429 diff changeset	1502 (see <a href="#fn_calls">Function Calls</a>).
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1503
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1504
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1505 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1506 The field list can have an optional trailing separator,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1507 as a convenience for machine-generated code.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1508
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1509
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1510
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1511
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1512
479 1285c52ea9d4 add manual heading_options Franklin Schmidt <fschmidt@gmail.com> parents: 478 diff changeset	1513 <h4 <%=heading_options%> ><a name="fn_calls">Function Calls</a></h4>
417 a40e99cf0b0b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 396 diff changeset	1514
a40e99cf0b0b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 396 diff changeset	1515 <p>
a40e99cf0b0b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 396 diff changeset	1516 A function call in Luan has the following syntax:
a40e99cf0b0b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 396 diff changeset	1517
a40e99cf0b0b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 396 diff changeset	1518 <p><tt><pre>
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1519 functioncall ::= prefixexp args
417 a40e99cf0b0b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 396 diff changeset	1520 </pre></tt></p>
a40e99cf0b0b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 396 diff changeset	1521
a40e99cf0b0b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 396 diff changeset	1522 <p>
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1523 In a function call,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1524 first prefixexp and args are evaluated.
417 a40e99cf0b0b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 396 diff changeset	1525 If the value of prefixexp has type <i>function</i>,
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1526 then this function is called
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1527 with the given arguments.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1528 Otherwise, the prefixexp "call" metamethod is called,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1529 having as first parameter the value of prefixexp,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1530 followed by the original call arguments
464 eddf7c73373b fix references in the manual Franklin Schmidt <fschmidt@gmail.com> parents: 429 diff changeset	1531 (see <a href="#meta">Metatables and Metamethods</a>).
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1532
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1533
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1534 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1535 Arguments have the following syntax:
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1536
417 a40e99cf0b0b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 396 diff changeset	1537 <p><tt><pre>
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1538 args ::= ‘<b>(</b>’ [explist] ‘<b>)</b>’
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1539 args ::= tableconstructor
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1540 args ::= LiteralString
417 a40e99cf0b0b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 396 diff changeset	1541 </pre></tt></p>
a40e99cf0b0b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 396 diff changeset	1542
a40e99cf0b0b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 396 diff changeset	1543 <p>
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1544 All argument expressions are evaluated before the call.
417 a40e99cf0b0b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 396 diff changeset	1545 A call of the form <tt>f{<i>fields</i>}</tt> is
a40e99cf0b0b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 396 diff changeset	1546 syntactic sugar for <tt>f({<i>fields</i>})</tt>;
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1547 that is, the argument list is a single new table.
417 a40e99cf0b0b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 396 diff changeset	1548 A call of the form <tt>f'<i>string</i>'</tt>
a40e99cf0b0b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 396 diff changeset	1549 (or <tt>f"<i>string</i>"</tt> or <tt>f[[<i>string</i>]]</tt>)
a40e99cf0b0b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 396 diff changeset	1550 is syntactic sugar for <tt>f('<i>string</i>')</tt>;
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1551 that is, the argument list is a single literal string.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1552
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1553
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1554 <p>
417 a40e99cf0b0b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 396 diff changeset	1555 A call of the form <tt>return <i>functioncall</i></tt> is called
a40e99cf0b0b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 396 diff changeset	1556 a <i>tail call</i>.
a40e99cf0b0b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 396 diff changeset	1557 Luan implements <i>proper tail calls</i>
a40e99cf0b0b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 396 diff changeset	1558 (or <i>proper tail recursion</i>):
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1559 in a tail call,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1560 the called function reuses the stack entry of the calling function.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1561 Therefore, there is no limit on the number of nested tail calls that
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1562 a program can execute.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1563 However, a tail call erases any debug information about the
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1564 calling function.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1565 Note that a tail call only happens with a particular syntax,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1566 where the <b>return</b> has one single function call as argument;
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1567 this syntax makes the calling function return exactly
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1568 the returns of the called function.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1569 So, none of the following examples are tail calls:
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1570
417 a40e99cf0b0b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 396 diff changeset	1571 <p><tt><pre>
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1572 return (f(x)) -- results adjusted to 1
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1573 return 2 * f(x)
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1574 return x, f(x) -- additional results
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1575 f(x); return -- results discarded
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1576 return x or f(x) -- results adjusted to 1
417 a40e99cf0b0b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 396 diff changeset	1577 </pre></tt></p>
a40e99cf0b0b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 396 diff changeset	1578
a40e99cf0b0b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 396 diff changeset	1579
a40e99cf0b0b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 396 diff changeset	1580
a40e99cf0b0b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 396 diff changeset	1581
479 1285c52ea9d4 add manual heading_options Franklin Schmidt <fschmidt@gmail.com> parents: 478 diff changeset	1582 <h4 <%=heading_options%> ><a name="fn_def">Function Definitions</a></h4>
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1583
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1584 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1585 The syntax for function definition is
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1586
417 a40e99cf0b0b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 396 diff changeset	1587 <p><tt><pre>
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1588 functiondef ::= <b>function</b> funcbody
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1589 funcbody ::= ‘<b>(</b>’ [parlist] ‘<b>)</b>’ block <b>end</b>
417 a40e99cf0b0b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 396 diff changeset	1590 </pre></tt></p>
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1591
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1592 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1593 The following syntactic sugar simplifies function definitions:
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1594
417 a40e99cf0b0b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 396 diff changeset	1595 <p><tt><pre>
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1596 stat ::= <b>function</b> funcname funcbody
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1597 stat ::= <b>local</b> <b>function</b> Name funcbody
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1598 funcname ::= Name {‘<b>.</b>’ Name} [‘<b>:</b>’ Name]
417 a40e99cf0b0b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 396 diff changeset	1599 </pre></tt></p>
a40e99cf0b0b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 396 diff changeset	1600
a40e99cf0b0b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 396 diff changeset	1601 <p>
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1602 The statement
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1603
417 a40e99cf0b0b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 396 diff changeset	1604 <p><tt><pre>
a40e99cf0b0b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 396 diff changeset	1605 function f () <i>body</i> end
a40e99cf0b0b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 396 diff changeset	1606 </pre></tt></p>
a40e99cf0b0b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 396 diff changeset	1607
a40e99cf0b0b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 396 diff changeset	1608 <p>
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1609 translates to
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1610
417 a40e99cf0b0b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 396 diff changeset	1611 <p><tt><pre>
a40e99cf0b0b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 396 diff changeset	1612 f = function () <i>body</i> end
a40e99cf0b0b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 396 diff changeset	1613 </pre></tt></p>
a40e99cf0b0b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 396 diff changeset	1614
a40e99cf0b0b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 396 diff changeset	1615 <p>
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1616 The statement
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1617
417 a40e99cf0b0b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 396 diff changeset	1618 <p><tt><pre>
a40e99cf0b0b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 396 diff changeset	1619 function t.a.b.c.f () <i>body</i> end
a40e99cf0b0b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 396 diff changeset	1620 </pre></tt></p>
a40e99cf0b0b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 396 diff changeset	1621
a40e99cf0b0b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 396 diff changeset	1622 <p>
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1623 translates to
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1624
417 a40e99cf0b0b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 396 diff changeset	1625 <p><tt><pre>
a40e99cf0b0b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 396 diff changeset	1626 t.a.b.c.f = function () <i>body</i> end
a40e99cf0b0b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 396 diff changeset	1627 </pre></tt></p>
a40e99cf0b0b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 396 diff changeset	1628
a40e99cf0b0b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 396 diff changeset	1629 <p>
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1630 The statement
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1631
417 a40e99cf0b0b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 396 diff changeset	1632 <p><tt><pre>
a40e99cf0b0b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 396 diff changeset	1633 local function f () <i>body</i> end
a40e99cf0b0b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 396 diff changeset	1634 </pre></tt></p>
a40e99cf0b0b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 396 diff changeset	1635
a40e99cf0b0b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 396 diff changeset	1636 <p>
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1637 translates to
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1638
417 a40e99cf0b0b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 396 diff changeset	1639 <p><tt><pre>
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1640 local f; f = function () <em>body</em> end
417 a40e99cf0b0b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 396 diff changeset	1641 </pre></tt></p>
a40e99cf0b0b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 396 diff changeset	1642
a40e99cf0b0b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 396 diff changeset	1643 <p>
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1644 not to
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1645
417 a40e99cf0b0b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 396 diff changeset	1646 <p><tt><pre>
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1647 local f = function () <em>body</em> end
417 a40e99cf0b0b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 396 diff changeset	1648 </pre></tt></p>
a40e99cf0b0b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 396 diff changeset	1649
a40e99cf0b0b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 396 diff changeset	1650 <p>
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1651 (This only makes a difference when the body of the function
417 a40e99cf0b0b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 396 diff changeset	1652 contains references to <tt>f</tt>.)
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1653
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1654
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1655 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1656 A function definition is an executable expression,
417 a40e99cf0b0b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 396 diff changeset	1657 whose value has type <i>function</i>.
a40e99cf0b0b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 396 diff changeset	1658 When Luan precompiles a chunk,
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1659 all its function bodies are precompiled too.
417 a40e99cf0b0b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 396 diff changeset	1660 Then, whenever Luan executes the function definition,
a40e99cf0b0b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 396 diff changeset	1661 the function is <i>instantiated</i> (or <i>closed</i>).
a40e99cf0b0b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 396 diff changeset	1662 This function instance (or <i>closure</i>)
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1663 is the final value of the expression.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1664
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1665
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1666 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1667 Parameters act as local variables that are
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1668 initialized with the argument values:
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1669
417 a40e99cf0b0b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 396 diff changeset	1670 <p><tt><pre>
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1671 parlist ::= namelist [‘<b>,</b>’ ‘<b>...</b>’] \| ‘<b>...</b>’
417 a40e99cf0b0b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 396 diff changeset	1672 </pre></tt></p>
a40e99cf0b0b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 396 diff changeset	1673
a40e99cf0b0b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 396 diff changeset	1674 <p>
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1675 When a function is called,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1676 the list of arguments is adjusted to
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1677 the length of the list of parameters,
417 a40e99cf0b0b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 396 diff changeset	1678 unless the function is a <i>vararg function</i>,
a40e99cf0b0b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 396 diff changeset	1679 which is indicated by three dots ('<tt>...</tt>')
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1680 at the end of its parameter list.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1681 A vararg function does not adjust its argument list;
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1682 instead, it collects all extra arguments and supplies them
417 a40e99cf0b0b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 396 diff changeset	1683 to the function through a <i>vararg expression</i>,
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1684 which is also written as three dots.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1685 The value of this expression is a list of all actual extra arguments,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1686 similar to a function with multiple results.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1687 If a vararg expression is used inside another expression
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1688 or in the middle of a list of expressions,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1689 then its return list is adjusted to one element.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1690 If the expression is used as the last element of a list of expressions,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1691 then no adjustment is made
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1692 (unless that last expression is enclosed in parentheses).
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1693
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1694
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1695 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1696 As an example, consider the following definitions:
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1697
417 a40e99cf0b0b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 396 diff changeset	1698 <p><tt><pre>
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1699 function f(a, b) end
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1700 function g(a, b, ...) end
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1701 function r() return 1,2,3 end
417 a40e99cf0b0b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 396 diff changeset	1702 </pre></tt></p>
a40e99cf0b0b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 396 diff changeset	1703
a40e99cf0b0b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 396 diff changeset	1704 <p>
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1705 Then, we have the following mapping from arguments to parameters and
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1706 to the vararg expression:
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1707
417 a40e99cf0b0b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 396 diff changeset	1708 <p><tt><pre>
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1709 CALL PARAMETERS
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1710
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1711 f(3) a=3, b=nil
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1712 f(3, 4) a=3, b=4
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1713 f(3, 4, 5) a=3, b=4
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1714 f(r(), 10) a=1, b=10
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1715 f(r()) a=1, b=2
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1716
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1717 g(3) a=3, b=nil, ... --> (nothing)
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1718 g(3, 4) a=3, b=4, ... --> (nothing)
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1719 g(3, 4, 5, 8) a=3, b=4, ... --> 5 8
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1720 g(5, r()) a=5, b=1, ... --> 2 3
417 a40e99cf0b0b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 396 diff changeset	1721 </pre></tt></p>
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1722
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1723 <p>
464 eddf7c73373b fix references in the manual Franklin Schmidt <fschmidt@gmail.com> parents: 429 diff changeset	1724 Results are returned using the <b>return</b> statement (see <a href="#control">Control Structures</a>).
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1725 If control reaches the end of a function
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1726 without encountering a <b>return</b> statement,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1727 then the function returns with no results.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1728
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1729
479 1285c52ea9d4 add manual heading_options Franklin Schmidt <fschmidt@gmail.com> parents: 478 diff changeset	1730 <h4 <%=heading_options%> ><a name="template_expr">Template Expressions</a></h4>
465 47c7de1f2322 documentation work Franklin Schmidt <fschmidt@gmail.com> parents: 464 diff changeset	1731
47c7de1f2322 documentation work Franklin Schmidt <fschmidt@gmail.com> parents: 464 diff changeset	1732 <p>Luan template expression are based on <a href="http://en.wikipedia.org/wiki/JavaServer_Pages">JSP</a>. Template expressions return multiple values. Here is an example:</p>
47c7de1f2322 documentation work Franklin Schmidt <fschmidt@gmail.com> parents: 464 diff changeset	1733
47c7de1f2322 documentation work Franklin Schmidt <fschmidt@gmail.com> parents: 464 diff changeset	1734 <p><tt><pre><%=Html.encode[[
47c7de1f2322 documentation work Franklin Schmidt <fschmidt@gmail.com> parents: 464 diff changeset	1735 local name = "Bob"
469 85467f95ab13 minor Franklin Schmidt <fschmidt@gmail.com> parents: 468 diff changeset	1736 write( %>Hello <%= name %>!<% )
465 47c7de1f2322 documentation work Franklin Schmidt <fschmidt@gmail.com> parents: 464 diff changeset	1737 ]]%></pre></tt></p>
47c7de1f2322 documentation work Franklin Schmidt <fschmidt@gmail.com> parents: 464 diff changeset	1738
47c7de1f2322 documentation work Franklin Schmidt <fschmidt@gmail.com> parents: 464 diff changeset	1739 <p>This is equivalent to the code:</p>
47c7de1f2322 documentation work Franklin Schmidt <fschmidt@gmail.com> parents: 464 diff changeset	1740
47c7de1f2322 documentation work Franklin Schmidt <fschmidt@gmail.com> parents: 464 diff changeset	1741 <p><tt><pre>
47c7de1f2322 documentation work Franklin Schmidt <fschmidt@gmail.com> parents: 464 diff changeset	1742 local name = "Bob"
47c7de1f2322 documentation work Franklin Schmidt <fschmidt@gmail.com> parents: 464 diff changeset	1743 write( "Hello ", name, "!" )
47c7de1f2322 documentation work Franklin Schmidt <fschmidt@gmail.com> parents: 464 diff changeset	1744 </pre></tt></p>
47c7de1f2322 documentation work Franklin Schmidt <fschmidt@gmail.com> parents: 464 diff changeset	1745
47c7de1f2322 documentation work Franklin Schmidt <fschmidt@gmail.com> parents: 464 diff changeset	1746 <p>The strings in template expressions may be multiple lines.</p>
47c7de1f2322 documentation work Franklin Schmidt <fschmidt@gmail.com> parents: 464 diff changeset	1747
417 a40e99cf0b0b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 396 diff changeset	1748
a40e99cf0b0b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 396 diff changeset	1749
479 1285c52ea9d4 add manual heading_options Franklin Schmidt <fschmidt@gmail.com> parents: 478 diff changeset	1750 <h3 <%=heading_options%> ><a name="visibility">Visibility Rules</a></h3>
417 a40e99cf0b0b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 396 diff changeset	1751
a40e99cf0b0b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 396 diff changeset	1752 <p>
a40e99cf0b0b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 396 diff changeset	1753 Luan is a lexically scoped language.
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1754 The scope of a local variable begins at the first statement after
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1755 its declaration and lasts until the last non-void statement
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1756 of the innermost block that includes the declaration.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1757 Consider the following example:
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1758
417 a40e99cf0b0b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 396 diff changeset	1759 <p><tt><pre>
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1760 x = 10 -- global variable
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1761 do -- new block
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1762 local x = x -- new 'x', with value 10
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1763 print(x) --> 10
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1764 x = x+1
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1765 do -- another block
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1766 local x = x+1 -- another 'x'
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1767 print(x) --> 12
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1768 end
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1769 print(x) --> 11
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1770 end
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1771 print(x) --> 10 (the global one)
417 a40e99cf0b0b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 396 diff changeset	1772 </pre></tt></p>
a40e99cf0b0b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 396 diff changeset	1773
a40e99cf0b0b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 396 diff changeset	1774 <p>
a40e99cf0b0b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 396 diff changeset	1775 Notice that, in a declaration like <tt>local x = x</tt>,
a40e99cf0b0b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 396 diff changeset	1776 the new <tt>x</tt> being declared is not in scope yet,
a40e99cf0b0b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 396 diff changeset	1777 and so the second <tt>x</tt> refers to the outside variable.
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1778
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1779
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1780 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1781 Because of the lexical scoping rules,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1782 local variables can be freely accessed by functions
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1783 defined inside their scope.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1784 A local variable used by an inner function is called
417 a40e99cf0b0b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 396 diff changeset	1785 an <i>upvalue</i>, or <i>external local variable</i>,
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1786 inside the inner function.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1787
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1788
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1789 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1790 Notice that each execution of a <b>local</b> statement
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1791 defines new local variables.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1792 Consider the following example:
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1793
417 a40e99cf0b0b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 396 diff changeset	1794 <p><tt><pre>
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1795 a = {}
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1796 local x = 20
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1797 for i=1,10 do
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1798 local y = 0
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1799 a[i] = function () y=y+1; return x+y end
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1800 end
417 a40e99cf0b0b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 396 diff changeset	1801 </pre></tt></p>
a40e99cf0b0b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 396 diff changeset	1802
a40e99cf0b0b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 396 diff changeset	1803 <p>
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1804 The loop creates ten closures
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1805 (that is, ten instances of the anonymous function).
417 a40e99cf0b0b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 396 diff changeset	1806 Each of these closures uses a different <tt>y</tt> variable,
a40e99cf0b0b work on manual Franklin Schmidt <fschmidt@gmail.com> parents: 396 diff changeset	1807 while all of them share the same <tt>x</tt>.
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1808
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1809
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1810
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1811
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1812
479 1285c52ea9d4 add manual heading_options Franklin Schmidt <fschmidt@gmail.com> parents: 478 diff changeset	1813 <h2 <%=heading_options%> ><a name="libs">Standard Libraries</a></h2>
468 9b51e2413cab documentation Franklin Schmidt <fschmidt@gmail.com> parents: 465 diff changeset	1814
9b51e2413cab documentation Franklin Schmidt <fschmidt@gmail.com> parents: 465 diff changeset	1815 <p>
9b51e2413cab documentation Franklin Schmidt <fschmidt@gmail.com> parents: 465 diff changeset	1816 The standard Luan libraries provide useful functions
9b51e2413cab documentation Franklin Schmidt <fschmidt@gmail.com> parents: 465 diff changeset	1817 that are implemented both in Java and in Luan itself.
9b51e2413cab documentation Franklin Schmidt <fschmidt@gmail.com> parents: 465 diff changeset	1818 How each function is implemented shouldn't matter to the user.
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1819 Some of these functions provide essential services to the language
478 eb6d90fb0b5c documentation Franklin Schmidt <fschmidt@gmail.com> parents: 476 diff changeset	1820 (e.g., <a href="#Luan.type"><tt>type</tt></a> and <a href="#Luan.get_metatable"><tt>get_metatable</tt></a>);
468 9b51e2413cab documentation Franklin Schmidt <fschmidt@gmail.com> parents: 465 diff changeset	1821 others provide access to "outside" services (e.g., I/O).
9b51e2413cab documentation Franklin Schmidt <fschmidt@gmail.com> parents: 465 diff changeset	1822
9b51e2413cab documentation Franklin Schmidt <fschmidt@gmail.com> parents: 465 diff changeset	1823
479 1285c52ea9d4 add manual heading_options Franklin Schmidt <fschmidt@gmail.com> parents: 478 diff changeset	1824 <h3 <%=heading_options%> ><a name="default_lib">Default Environment</a></h3>
468 9b51e2413cab documentation Franklin Schmidt <fschmidt@gmail.com> parents: 465 diff changeset	1825
9b51e2413cab documentation Franklin Schmidt <fschmidt@gmail.com> parents: 465 diff changeset	1826 <p>
9b51e2413cab documentation Franklin Schmidt <fschmidt@gmail.com> parents: 465 diff changeset	1827 These are provided by default as local variables for any Luan code as described in <a href="#env">Environments</a>.
9b51e2413cab documentation Franklin Schmidt <fschmidt@gmail.com> parents: 465 diff changeset	1828
470 5627eb637eb4 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 469 diff changeset	1829
479 1285c52ea9d4 add manual heading_options Franklin Schmidt <fschmidt@gmail.com> parents: 478 diff changeset	1830 <h4 <%=heading_options%> ><a name="_ENV"><tt>_ENV</tt></a></h4>
468 9b51e2413cab documentation Franklin Schmidt <fschmidt@gmail.com> parents: 465 diff changeset	1831
9b51e2413cab documentation Franklin Schmidt <fschmidt@gmail.com> parents: 465 diff changeset	1832 <p>
9b51e2413cab documentation Franklin Schmidt <fschmidt@gmail.com> parents: 465 diff changeset	1833 This is a table that holds the global variables of a module as described in <a href="#env">Environments</a>.
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1834
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1835
479 1285c52ea9d4 add manual heading_options Franklin Schmidt <fschmidt@gmail.com> parents: 478 diff changeset	1836 <h4 <%=heading_options%> ><a name="require"><tt>java ()</tt></a></h4>
470 5627eb637eb4 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 469 diff changeset	1837
5627eb637eb4 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 469 diff changeset	1838 <p>
5627eb637eb4 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 469 diff changeset	1839 This function 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.
5627eb637eb4 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 469 diff changeset	1840
5627eb637eb4 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 469 diff changeset	1841
479 1285c52ea9d4 add manual heading_options Franklin Schmidt <fschmidt@gmail.com> parents: 478 diff changeset	1842 <h4 <%=heading_options%> ><a name="require"><tt>require (mod_uri)</tt></a></h4>
470 5627eb637eb4 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 469 diff changeset	1843
5627eb637eb4 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 469 diff changeset	1844 <p>
5627eb637eb4 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 469 diff changeset	1845 Example use:
5627eb637eb4 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 469 diff changeset	1846
5627eb637eb4 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 469 diff changeset	1847 <p><tt><pre>
5627eb637eb4 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 469 diff changeset	1848 local Table = require "luan:Table"
5627eb637eb4 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 469 diff changeset	1849 </pre></tt></p>
5627eb637eb4 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 469 diff changeset	1850
5627eb637eb4 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 469 diff changeset	1851 <p>
5627eb637eb4 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 469 diff changeset	1852 Could be defined as:
5627eb637eb4 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 469 diff changeset	1853
5627eb637eb4 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 469 diff changeset	1854 <p><tt><pre>
5627eb637eb4 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 469 diff changeset	1855 local function require(mod_name)
476 cd22e4694ea3 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 475 diff changeset	1856 return <a href="#Package.load">Package.load</a>(mod_name) or <a href="#Luan.error">Luan.error</a>("module '"..mod_name.."' not found")
470 5627eb637eb4 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 469 diff changeset	1857 end
5627eb637eb4 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 469 diff changeset	1858 </pre></tt></p>
5627eb637eb4 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 469 diff changeset	1859
5627eb637eb4 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 469 diff changeset	1860
479 1285c52ea9d4 add manual heading_options Franklin Schmidt <fschmidt@gmail.com> parents: 478 diff changeset	1861 <h3 <%=heading_options%> ><a name="luan_lib">Basic Functions</a></h3>
470 5627eb637eb4 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 469 diff changeset	1862
5627eb637eb4 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 469 diff changeset	1863 <p>
5627eb637eb4 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 469 diff changeset	1864 Include this library by:
5627eb637eb4 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 469 diff changeset	1865
5627eb637eb4 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 469 diff changeset	1866 <p><tt><pre>
5627eb637eb4 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 469 diff changeset	1867 local Luan = require "luan:Luan"
5627eb637eb4 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 469 diff changeset	1868 </pre></tt></p>
5627eb637eb4 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 469 diff changeset	1869
476 cd22e4694ea3 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 475 diff changeset	1870 <p>
470 5627eb637eb4 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 469 diff changeset	1871 The basic library provides basic functions to Luan that don't depend on other libaries.
5627eb637eb4 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 469 diff changeset	1872
5627eb637eb4 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 469 diff changeset	1873
479 1285c52ea9d4 add manual heading_options Franklin Schmidt <fschmidt@gmail.com> parents: 478 diff changeset	1874 <h4 <%=heading_options%> ><a name="Luan.assert"><tt>Luan.assert (v [, message])</tt></a></h4>
470 5627eb637eb4 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 469 diff changeset	1875
5627eb637eb4 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 469 diff changeset	1876 <p>
5627eb637eb4 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 469 diff changeset	1877 Could be defined as:
5627eb637eb4 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 469 diff changeset	1878
5627eb637eb4 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 469 diff changeset	1879 <p><tt><pre>
5627eb637eb4 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 469 diff changeset	1880 function Luan.assert(v,message)
472 f4aca5a5346a minor documentation Franklin Schmidt <fschmidt@gmail.com> parents: 470 diff changeset	1881 return v or <a href="#Luan.error">Luan.error</a>(message or "assertion failed!")
470 5627eb637eb4 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 469 diff changeset	1882 end
5627eb637eb4 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 469 diff changeset	1883 </pre></tt></p>
5627eb637eb4 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 469 diff changeset	1884
5627eb637eb4 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 469 diff changeset	1885
479 1285c52ea9d4 add manual heading_options Franklin Schmidt <fschmidt@gmail.com> parents: 478 diff changeset	1886 <h4 <%=heading_options%> ><a name="Luan.assert_binary"><tt>Luan.assert_binary (v)</tt></a></h4>
470 5627eb637eb4 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 469 diff changeset	1887
5627eb637eb4 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 469 diff changeset	1888 <p>
5627eb637eb4 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 469 diff changeset	1889 Could be defined as:
5627eb637eb4 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 469 diff changeset	1890
5627eb637eb4 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 469 diff changeset	1891 <p><tt><pre>
5627eb637eb4 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 469 diff changeset	1892 function Luan.assert_binary(v)
5627eb637eb4 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 469 diff changeset	1893 local v_type = Luan.type(v)
472 f4aca5a5346a minor documentation Franklin Schmidt <fschmidt@gmail.com> parents: 470 diff changeset	1894 return v_type == "binary" and v or <a href="#Luan.error">Luan.error</a>("bad argument #1 (binary expected, got "..v_type..")")
470 5627eb637eb4 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 469 diff changeset	1895 end
5627eb637eb4 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 469 diff changeset	1896 </pre></tt></p>
5627eb637eb4 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 469 diff changeset	1897
5627eb637eb4 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 469 diff changeset	1898
479 1285c52ea9d4 add manual heading_options Franklin Schmidt <fschmidt@gmail.com> parents: 478 diff changeset	1899 <h4 <%=heading_options%> ><a name="Luan.assert_boolean"><tt>Luan.assert_boolean (v)</tt></a></h4>
470 5627eb637eb4 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 469 diff changeset	1900
5627eb637eb4 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 469 diff changeset	1901 <p>
5627eb637eb4 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 469 diff changeset	1902 Like <a href="#Luan.assert_binary"><tt>assert_binary</tt></a> but for type <tt>boolean</tt>.
5627eb637eb4 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 469 diff changeset	1903
5627eb637eb4 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 469 diff changeset	1904
479 1285c52ea9d4 add manual heading_options Franklin Schmidt <fschmidt@gmail.com> parents: 478 diff changeset	1905 <h4 <%=heading_options%> ><a name="Luan.assert_integer"><tt>Luan.assert_integer (v)</tt></a></h4>
470 5627eb637eb4 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 469 diff changeset	1906
5627eb637eb4 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 469 diff changeset	1907 <p>
5627eb637eb4 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 469 diff changeset	1908 Asserts that <tt>v</tt> can be converted to Java type <a href="https://docs.oracle.com/javase/8/docs/api/java/lang/Integer.html">Integer</a> and returns an Integer.
5627eb637eb4 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 469 diff changeset	1909
5627eb637eb4 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 469 diff changeset	1910
479 1285c52ea9d4 add manual heading_options Franklin Schmidt <fschmidt@gmail.com> parents: 478 diff changeset	1911 <h4 <%=heading_options%> ><a name="Luan.assert_long"><tt>Luan.assert_long (v)</tt></a></h4>
470 5627eb637eb4 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 469 diff changeset	1912
5627eb637eb4 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 469 diff changeset	1913 <p>
5627eb637eb4 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 469 diff changeset	1914 Asserts that <tt>v</tt> can be converted to Java type <a href="https://docs.oracle.com/javase/8/docs/api/java/lang/Long.html">Long</a> and returns a Long.
5627eb637eb4 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 469 diff changeset	1915
5627eb637eb4 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 469 diff changeset	1916
479 1285c52ea9d4 add manual heading_options Franklin Schmidt <fschmidt@gmail.com> parents: 478 diff changeset	1917 <h4 <%=heading_options%> ><a name="Luan.assert_number"><tt>Luan.assert_number (v)</tt></a></h4>
470 5627eb637eb4 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 469 diff changeset	1918
5627eb637eb4 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 469 diff changeset	1919 <p>
5627eb637eb4 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 469 diff changeset	1920 Like <a href="#Luan.assert_binary"><tt>assert_binary</tt></a> but for type <tt>number</tt>.
5627eb637eb4 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 469 diff changeset	1921
5627eb637eb4 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 469 diff changeset	1922
479 1285c52ea9d4 add manual heading_options Franklin Schmidt <fschmidt@gmail.com> parents: 478 diff changeset	1923 <h4 <%=heading_options%> ><a name="Luan.assert_string"><tt>Luan.assert_string (v)</tt></a></h4>
470 5627eb637eb4 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 469 diff changeset	1924
5627eb637eb4 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 469 diff changeset	1925 <p>
5627eb637eb4 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 469 diff changeset	1926 Like <a href="#Luan.assert_binary"><tt>assert_binary</tt></a> but for type <tt>string</tt>.
5627eb637eb4 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 469 diff changeset	1927
5627eb637eb4 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 469 diff changeset	1928
479 1285c52ea9d4 add manual heading_options Franklin Schmidt <fschmidt@gmail.com> parents: 478 diff changeset	1929 <h4 <%=heading_options%> ><a name="Luan.assert_table"><tt>Luan.assert_table (v)</tt></a></h4>
470 5627eb637eb4 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 469 diff changeset	1930
5627eb637eb4 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 469 diff changeset	1931 <p>
5627eb637eb4 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 469 diff changeset	1932 Like <a href="#Luan.assert_binary"><tt>assert_binary</tt></a> but for type <tt>table</tt>.
5627eb637eb4 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 469 diff changeset	1933
5627eb637eb4 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 469 diff changeset	1934
479 1285c52ea9d4 add manual heading_options Franklin Schmidt <fschmidt@gmail.com> parents: 478 diff changeset	1935 <h4 <%=heading_options%> ><a name="Luan.do_file"><tt>Luan.do_file ([uri])</tt></a></h4>
470 5627eb637eb4 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 469 diff changeset	1936
5627eb637eb4 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 469 diff changeset	1937 <p>
5627eb637eb4 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 469 diff changeset	1938 Could be defined as:
5627eb637eb4 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 469 diff changeset	1939
5627eb637eb4 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 469 diff changeset	1940 <p><tt><pre>
5627eb637eb4 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 469 diff changeset	1941 function Luan.do_file(uri)
474 00646edc9d92 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 472 diff changeset	1942 return <a href="#Luan.load_file">Luan.load_file</a>(uri)()
470 5627eb637eb4 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 469 diff changeset	1943 end
5627eb637eb4 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 469 diff changeset	1944 </pre></tt></p>
5627eb637eb4 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 469 diff changeset	1945
5627eb637eb4 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 469 diff changeset	1946
5627eb637eb4 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 469 diff changeset	1947
479 1285c52ea9d4 add manual heading_options Franklin Schmidt <fschmidt@gmail.com> parents: 478 diff changeset	1948 <h4 <%=heading_options%> ><a name="Luan.error"><tt>Luan.error (message)</tt></a></h4>
470 5627eb637eb4 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 469 diff changeset	1949
5627eb637eb4 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 469 diff changeset	1950 <p>
482 7e9fcfbf22ec documentation Franklin Schmidt <fschmidt@gmail.com> parents: 479 diff changeset	1951 Throws an error containing the message.
7e9fcfbf22ec documentation Franklin Schmidt <fschmidt@gmail.com> parents: 479 diff changeset	1952
7e9fcfbf22ec documentation Franklin Schmidt <fschmidt@gmail.com> parents: 479 diff changeset	1953 <p>
7e9fcfbf22ec documentation Franklin Schmidt <fschmidt@gmail.com> parents: 479 diff changeset	1954 Could be defined as:
7e9fcfbf22ec documentation Franklin Schmidt <fschmidt@gmail.com> parents: 479 diff changeset	1955
7e9fcfbf22ec documentation Franklin Schmidt <fschmidt@gmail.com> parents: 479 diff changeset	1956 <p><tt><pre>
7e9fcfbf22ec documentation Franklin Schmidt <fschmidt@gmail.com> parents: 479 diff changeset	1957 function Luan.error(message)
7e9fcfbf22ec documentation Franklin Schmidt <fschmidt@gmail.com> parents: 479 diff changeset	1958 <a href="#Luan.new_error">Luan.new_error</a>(message).throw()
7e9fcfbf22ec documentation Franklin Schmidt <fschmidt@gmail.com> parents: 479 diff changeset	1959 end
7e9fcfbf22ec documentation Franklin Schmidt <fschmidt@gmail.com> parents: 479 diff changeset	1960 </pre></tt></p>
7e9fcfbf22ec documentation Franklin Schmidt <fschmidt@gmail.com> parents: 479 diff changeset	1961
470 5627eb637eb4 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 469 diff changeset	1962
5627eb637eb4 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 469 diff changeset	1963
479 1285c52ea9d4 add manual heading_options Franklin Schmidt <fschmidt@gmail.com> parents: 478 diff changeset	1964 <h4 <%=heading_options%> ><a name="Luan.get_metatable"><tt>Luan.get_metatable (table)</tt></a></h4>
470 5627eb637eb4 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 469 diff changeset	1965
5627eb637eb4 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 469 diff changeset	1966 <p>
5627eb637eb4 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 469 diff changeset	1967 If <tt>table</tt> does not have a metatable, returns <b>nil</b>.
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1968 Otherwise,
470 5627eb637eb4 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 469 diff changeset	1969 if the table's metatable has a <tt>"__metatable"</tt> field,
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1970 returns the associated value.
470 5627eb637eb4 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 469 diff changeset	1971 Otherwise, returns the metatable of the given table.
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1972
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1973
479 1285c52ea9d4 add manual heading_options Franklin Schmidt <fschmidt@gmail.com> parents: 478 diff changeset	1974 <h4 <%=heading_options%> ><a name="Luan.ipairs"><tt>Luan.ipairs (t)</tt></a></h4>
474 00646edc9d92 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 472 diff changeset	1975
00646edc9d92 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 472 diff changeset	1976 <p>
00646edc9d92 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 472 diff changeset	1977 Returns an iterator function
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1978 so that the construction
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1979
474 00646edc9d92 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 472 diff changeset	1980 <p><tt><pre>
00646edc9d92 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 472 diff changeset	1981 for i,v in ipairs(t) do <i>body</i> end
00646edc9d92 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 472 diff changeset	1982 </pre></tt></p>
00646edc9d92 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 472 diff changeset	1983
00646edc9d92 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 472 diff changeset	1984 <p>
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1985 will iterate over the key–value pairs
474 00646edc9d92 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 472 diff changeset	1986 (<tt>1,t[1]</tt>), (<tt>2,t[2]</tt>), ...,
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1987 up to the first nil value.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	1988
474 00646edc9d92 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 472 diff changeset	1989 <p>
00646edc9d92 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 472 diff changeset	1990 Could be defined as:
00646edc9d92 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 472 diff changeset	1991
00646edc9d92 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 472 diff changeset	1992 <p><tt><pre>
00646edc9d92 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 472 diff changeset	1993 function Luan.ipairs(t)
00646edc9d92 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 472 diff changeset	1994 local i = 0
00646edc9d92 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 472 diff changeset	1995 return function()
00646edc9d92 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 472 diff changeset	1996 if i < #t then
00646edc9d92 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 472 diff changeset	1997 i = i + 1
00646edc9d92 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 472 diff changeset	1998 return i, t[i]
00646edc9d92 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 472 diff changeset	1999 end
00646edc9d92 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 472 diff changeset	2000 end
00646edc9d92 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 472 diff changeset	2001 end
00646edc9d92 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 472 diff changeset	2002 </pre></tt></p>
00646edc9d92 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 472 diff changeset	2003
00646edc9d92 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 472 diff changeset	2004
00646edc9d92 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 472 diff changeset	2005
479 1285c52ea9d4 add manual heading_options Franklin Schmidt <fschmidt@gmail.com> parents: 478 diff changeset	2006 <h4 <%=heading_options%> ><a name="Luan.load"><tt>Luan.load (text, source_name [env, [, allow_expression]])</tt></a></h4>
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2007
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2008 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2009 Loads a chunk.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2010
474 00646edc9d92 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 472 diff changeset	2011 <p>
00646edc9d92 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 472 diff changeset	2012 The <tt>text</tt> is compiled.
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2013 If there are no syntactic errors,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2014 returns the compiled chunk as a function;
474 00646edc9d92 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 472 diff changeset	2015 otherwise, throws an error.
00646edc9d92 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 472 diff changeset	2016
00646edc9d92 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 472 diff changeset	2017 <p>
00646edc9d92 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 472 diff changeset	2018 The <tt>source_name</tt> parameter is a string saying where the text came from. It is used to produce error messages.
00646edc9d92 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 472 diff changeset	2019
00646edc9d92 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 472 diff changeset	2020 <p>
00646edc9d92 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 472 diff changeset	2021 If the <tt>env</tt> parameter is supplied, it becomes the <tt>_ENV</tt> of the chunk.
00646edc9d92 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 472 diff changeset	2022
00646edc9d92 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 472 diff changeset	2023 <p>
00646edc9d92 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 472 diff changeset	2024 If the <tt>allow_expression</tt> parameter is <tt>true</tt> then the entire text can be nothing more than an expression in which case the chunk returns the value of this expression.
00646edc9d92 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 472 diff changeset	2025
00646edc9d92 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 472 diff changeset	2026
479 1285c52ea9d4 add manual heading_options Franklin Schmidt <fschmidt@gmail.com> parents: 478 diff changeset	2027 <h4 <%=heading_options%> ><a name="Luan.load_file"><tt>Luan.load_file (file_uri [, add_extension])</tt></a></h4>
474 00646edc9d92 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 472 diff changeset	2028
00646edc9d92 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 472 diff changeset	2029 <p>
00646edc9d92 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 472 diff changeset	2030 Similar to <a href="#Luan.load"><tt>load</tt></a>,
00646edc9d92 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 472 diff changeset	2031 but gets the chunk from file <tt>file_uri</tt>
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2032 or from the standard input,
474 00646edc9d92 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 472 diff changeset	2033 if no file uri is given.
00646edc9d92 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 472 diff changeset	2034
00646edc9d92 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 472 diff changeset	2035 <p>
00646edc9d92 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 472 diff changeset	2036 Could be defined as:
00646edc9d92 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 472 diff changeset	2037
00646edc9d92 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 472 diff changeset	2038 <p><tt><pre>
00646edc9d92 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 472 diff changeset	2039 function Luan.load_file(file_uri,add_extension)
00646edc9d92 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 472 diff changeset	2040 file_uri = file_uri or "stdin:"
00646edc9d92 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 472 diff changeset	2041 local f = Io.uri(file_uri,add_extension)
00646edc9d92 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 472 diff changeset	2042 f.exists() or <a href="#Luan.error">Luan.error</a>("file '"..file_uri.."' not found")
00646edc9d92 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 472 diff changeset	2043 return <a href="#Luan.load">Luan.load</a>( f.read_text(), file_uri )
00646edc9d92 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 472 diff changeset	2044 end
00646edc9d92 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 472 diff changeset	2045 </pre></tt></p>
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2046
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2047
482 7e9fcfbf22ec documentation Franklin Schmidt <fschmidt@gmail.com> parents: 479 diff changeset	2048 <h4 <%=heading_options%> ><a name="Luan.new_error"><tt>Luan.new_error (message)</tt></a></h4>
7e9fcfbf22ec documentation Franklin Schmidt <fschmidt@gmail.com> parents: 479 diff changeset	2049
7e9fcfbf22ec documentation Franklin Schmidt <fschmidt@gmail.com> parents: 479 diff changeset	2050 <p>
7e9fcfbf22ec documentation Franklin Schmidt <fschmidt@gmail.com> parents: 479 diff changeset	2051 Creates a new error table containing the message assigned to "<tt>message</tt>". The error table also contains a <tt>throw</tt> function which throws the error. The table also contains a list of stack trace elements where each stack trace element is a table containing "<tt>source</tt>", "<tt>line</tt>", and possible "<tt>call_to</tt>". The table also has a metatable containing "<tt>__to_string</tt>" to render the error.
7e9fcfbf22ec documentation Franklin Schmidt <fschmidt@gmail.com> parents: 479 diff changeset	2052
7e9fcfbf22ec documentation Franklin Schmidt <fschmidt@gmail.com> parents: 479 diff changeset	2053 <p>
7e9fcfbf22ec documentation Franklin Schmidt <fschmidt@gmail.com> parents: 479 diff changeset	2054 To print the current stack trace, you could do:
7e9fcfbf22ec documentation Franklin Schmidt <fschmidt@gmail.com> parents: 479 diff changeset	2055
7e9fcfbf22ec documentation Franklin Schmidt <fschmidt@gmail.com> parents: 479 diff changeset	2056 <p><tt><pre>
7e9fcfbf22ec documentation Franklin Schmidt <fschmidt@gmail.com> parents: 479 diff changeset	2057 Io.print( Luan.new_error "stack" )
7e9fcfbf22ec documentation Franklin Schmidt <fschmidt@gmail.com> parents: 479 diff changeset	2058 </pre></tt></p>
7e9fcfbf22ec documentation Franklin Schmidt <fschmidt@gmail.com> parents: 479 diff changeset	2059
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2060
479 1285c52ea9d4 add manual heading_options Franklin Schmidt <fschmidt@gmail.com> parents: 478 diff changeset	2061 <h4 <%=heading_options%> ><a name="Luan.pairs"><tt>Luan.pairs (t)</tt></a></h4>
475 7ac0891718eb documentation Franklin Schmidt <fschmidt@gmail.com> parents: 474 diff changeset	2062
7ac0891718eb documentation Franklin Schmidt <fschmidt@gmail.com> parents: 474 diff changeset	2063 <p>
7ac0891718eb documentation Franklin Schmidt <fschmidt@gmail.com> parents: 474 diff changeset	2064 If <tt>t</tt> has a metamethod <tt>__pairs</tt>,
7ac0891718eb documentation Franklin Schmidt <fschmidt@gmail.com> parents: 474 diff changeset	2065 calls it with <tt>t</tt> as argument and returns the
7ac0891718eb documentation Franklin Schmidt <fschmidt@gmail.com> parents: 474 diff changeset	2066 result from the call.
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2067
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2068
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2069 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2070 Otherwise,
475 7ac0891718eb documentation Franklin Schmidt <fschmidt@gmail.com> parents: 474 diff changeset	2071 returns a function
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2072 so that the construction
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2073
475 7ac0891718eb documentation Franklin Schmidt <fschmidt@gmail.com> parents: 474 diff changeset	2074 <p><tt><pre>
7ac0891718eb documentation Franklin Schmidt <fschmidt@gmail.com> parents: 474 diff changeset	2075 for k,v in pairs(t) do <i>body</i> end
7ac0891718eb documentation Franklin Schmidt <fschmidt@gmail.com> parents: 474 diff changeset	2076 </pre></tt></p>
7ac0891718eb documentation Franklin Schmidt <fschmidt@gmail.com> parents: 474 diff changeset	2077
7ac0891718eb documentation Franklin Schmidt <fschmidt@gmail.com> parents: 474 diff changeset	2078 <p>
7ac0891718eb documentation Franklin Schmidt <fschmidt@gmail.com> parents: 474 diff changeset	2079 will iterate over all key–value pairs of table <tt>t</tt>.
7ac0891718eb documentation Franklin Schmidt <fschmidt@gmail.com> parents: 474 diff changeset	2080
7ac0891718eb documentation Franklin Schmidt <fschmidt@gmail.com> parents: 474 diff changeset	2081
7ac0891718eb documentation Franklin Schmidt <fschmidt@gmail.com> parents: 474 diff changeset	2082
479 1285c52ea9d4 add manual heading_options Franklin Schmidt <fschmidt@gmail.com> parents: 478 diff changeset	2083 <h4 <%=heading_options%> ><a name="Luan.pcall"><tt>Luan.pcall (f [, arg1, ···])</tt></a></h4>
475 7ac0891718eb documentation Franklin Schmidt <fschmidt@gmail.com> parents: 474 diff changeset	2084
7ac0891718eb documentation Franklin Schmidt <fschmidt@gmail.com> parents: 474 diff changeset	2085 <p>
7ac0891718eb documentation Franklin Schmidt <fschmidt@gmail.com> parents: 474 diff changeset	2086 Calls function <tt>f</tt> with
7ac0891718eb documentation Franklin Schmidt <fschmidt@gmail.com> parents: 474 diff changeset	2087 the given arguments in <i>protected mode</i>.
7ac0891718eb documentation Franklin Schmidt <fschmidt@gmail.com> parents: 474 diff changeset	2088 This means that any error inside <tt>f</tt> is not propagated;
7ac0891718eb documentation Franklin Schmidt <fschmidt@gmail.com> parents: 474 diff changeset	2089 instead, <tt>pcall</tt> catches the error
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2090 and returns a status code.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2091 Its first result is the status code (a boolean),
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2092 which is true if the call succeeds without errors.
475 7ac0891718eb documentation Franklin Schmidt <fschmidt@gmail.com> parents: 474 diff changeset	2093 In such case, <tt>pcall</tt> also returns all results from the call,
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2094 after this first result.
475 7ac0891718eb documentation Franklin Schmidt <fschmidt@gmail.com> parents: 474 diff changeset	2095 In case of any error, <tt>pcall</tt> returns <b>false</b> plus the error.
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2096
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2097
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2098
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2099
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2100 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2101 <hr><h3><a name="pdf-print"><code>print (···)</code></a></h3>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2102 Receives any number of arguments
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2103 and prints their values to <code>stdout</code>,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2104 using the <a href="#pdf-tostring"><code>tostring</code></a> function to convert each argument to a string.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2105 <code>print</code> is not intended for formatted output,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2106 but only as a quick way to show a value,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2107 for instance for debugging.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2108 For complete control over the output,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2109 use <a href="#pdf-string.format"><code>string.format</code></a> and <a href="#pdf-io.write"><code>io.write</code></a>.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2110
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2111
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2112
479 1285c52ea9d4 add manual heading_options Franklin Schmidt <fschmidt@gmail.com> parents: 478 diff changeset	2113 <h4 <%=heading_options%> ><a name="Luan.range"><tt>Luan.range (start, stop [, step])</tt></a></h4>
476 cd22e4694ea3 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 475 diff changeset	2114
cd22e4694ea3 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 475 diff changeset	2115 <p>
cd22e4694ea3 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 475 diff changeset	2116 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.
cd22e4694ea3 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 475 diff changeset	2117
cd22e4694ea3 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 475 diff changeset	2118 <p>
cd22e4694ea3 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 475 diff changeset	2119 Example use:
cd22e4694ea3 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 475 diff changeset	2120
cd22e4694ea3 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 475 diff changeset	2121 <p><tt><pre>
cd22e4694ea3 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 475 diff changeset	2122 for i in range(1,10) do
cd22e4694ea3 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 475 diff changeset	2123 Io.print("count up:",i)
cd22e4694ea3 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 475 diff changeset	2124 end
cd22e4694ea3 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 475 diff changeset	2125 for i in range(10,0,-1) do
cd22e4694ea3 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 475 diff changeset	2126 Io.print("count down:",i)
cd22e4694ea3 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 475 diff changeset	2127 end
cd22e4694ea3 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 475 diff changeset	2128 </pre></tt></p>
cd22e4694ea3 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 475 diff changeset	2129
cd22e4694ea3 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 475 diff changeset	2130 <p>
cd22e4694ea3 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 475 diff changeset	2131 Could be defined as:
cd22e4694ea3 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 475 diff changeset	2132
cd22e4694ea3 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 475 diff changeset	2133 <p><tt><pre>
cd22e4694ea3 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 475 diff changeset	2134 function Luan.range(start, stop, step)
cd22e4694ea3 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 475 diff changeset	2135 step = step or 1
478 eb6d90fb0b5c documentation Franklin Schmidt <fschmidt@gmail.com> parents: 476 diff changeset	2136 step == 0 and <a href="#Luan.error">Luan.error</a> "bad argument #3 (step may not be zero)"
476 cd22e4694ea3 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 475 diff changeset	2137 local i = start
cd22e4694ea3 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 475 diff changeset	2138 return function()
cd22e4694ea3 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 475 diff changeset	2139 if step > 0 and i <= stop or step < 0 and i >= stop then
cd22e4694ea3 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 475 diff changeset	2140 local rtn = i
cd22e4694ea3 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 475 diff changeset	2141 i = i + step
cd22e4694ea3 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 475 diff changeset	2142 return rtn
cd22e4694ea3 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 475 diff changeset	2143 end
cd22e4694ea3 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 475 diff changeset	2144 end
cd22e4694ea3 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 475 diff changeset	2145 end
cd22e4694ea3 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 475 diff changeset	2146 </pre></tt></p>
cd22e4694ea3 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 475 diff changeset	2147
cd22e4694ea3 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 475 diff changeset	2148
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2149
479 1285c52ea9d4 add manual heading_options Franklin Schmidt <fschmidt@gmail.com> parents: 478 diff changeset	2150 <h4 <%=heading_options%> ><a name="Luan.raw_equal"><tt>Luan.raw_equal (v1, v2)</tt></a></h4>
475 7ac0891718eb documentation Franklin Schmidt <fschmidt@gmail.com> parents: 474 diff changeset	2151
7ac0891718eb documentation Franklin Schmidt <fschmidt@gmail.com> parents: 474 diff changeset	2152 <p>
7ac0891718eb documentation Franklin Schmidt <fschmidt@gmail.com> parents: 474 diff changeset	2153 Checks whether <tt>v1</tt> is equal to <tt>v2</tt>,
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2154 without invoking any metamethod.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2155 Returns a boolean.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2156
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2157
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2158
479 1285c52ea9d4 add manual heading_options Franklin Schmidt <fschmidt@gmail.com> parents: 478 diff changeset	2159 <h4 <%=heading_options%> ><a name="Luan.raw_get"><tt>Luan.raw_get (table, index)</tt></a></h4>
475 7ac0891718eb documentation Franklin Schmidt <fschmidt@gmail.com> parents: 474 diff changeset	2160
7ac0891718eb documentation Franklin Schmidt <fschmidt@gmail.com> parents: 474 diff changeset	2161 <p>
7ac0891718eb documentation Franklin Schmidt <fschmidt@gmail.com> parents: 474 diff changeset	2162 Gets the real value of <tt>table[index]</tt>,
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2163 without invoking any metamethod.
475 7ac0891718eb documentation Franklin Schmidt <fschmidt@gmail.com> parents: 474 diff changeset	2164 <tt>table</tt> must be a table;
7ac0891718eb documentation Franklin Schmidt <fschmidt@gmail.com> parents: 474 diff changeset	2165 <tt>index</tt> may be any value.
7ac0891718eb documentation Franklin Schmidt <fschmidt@gmail.com> parents: 474 diff changeset	2166
7ac0891718eb documentation Franklin Schmidt <fschmidt@gmail.com> parents: 474 diff changeset	2167
7ac0891718eb documentation Franklin Schmidt <fschmidt@gmail.com> parents: 474 diff changeset	2168
479 1285c52ea9d4 add manual heading_options Franklin Schmidt <fschmidt@gmail.com> parents: 478 diff changeset	2169 <h4 <%=heading_options%> ><a name="Luan.raw_len"><tt>Luan.raw_len (v)</tt></a></h4>
475 7ac0891718eb documentation Franklin Schmidt <fschmidt@gmail.com> parents: 474 diff changeset	2170
7ac0891718eb documentation Franklin Schmidt <fschmidt@gmail.com> parents: 474 diff changeset	2171 <p>
7ac0891718eb documentation Franklin Schmidt <fschmidt@gmail.com> parents: 474 diff changeset	2172 Returns the length of the object <tt>v</tt>,
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2173 which must be a table or a string,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2174 without invoking any metamethod.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2175 Returns an integer.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2176
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2177
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2178
479 1285c52ea9d4 add manual heading_options Franklin Schmidt <fschmidt@gmail.com> parents: 478 diff changeset	2179 <h4 <%=heading_options%> ><a name="Luan.raw_set"><tt>Luan.raw_set (table, index, value)</tt></a></h4>
475 7ac0891718eb documentation Franklin Schmidt <fschmidt@gmail.com> parents: 474 diff changeset	2180
7ac0891718eb documentation Franklin Schmidt <fschmidt@gmail.com> parents: 474 diff changeset	2181 <p>
7ac0891718eb documentation Franklin Schmidt <fschmidt@gmail.com> parents: 474 diff changeset	2182 Sets the real value of <tt>table[index]</tt> to <tt>value</tt>,
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2183 without invoking any metamethod.
475 7ac0891718eb documentation Franklin Schmidt <fschmidt@gmail.com> parents: 474 diff changeset	2184 <tt>table</tt> must be a table,
7ac0891718eb documentation Franklin Schmidt <fschmidt@gmail.com> parents: 474 diff changeset	2185 <tt>index</tt> any value different from <b>nil</b>,
7ac0891718eb documentation Franklin Schmidt <fschmidt@gmail.com> parents: 474 diff changeset	2186 and <tt>value</tt> any Lua value.
7ac0891718eb documentation Franklin Schmidt <fschmidt@gmail.com> parents: 474 diff changeset	2187
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2188
479 1285c52ea9d4 add manual heading_options Franklin Schmidt <fschmidt@gmail.com> parents: 478 diff changeset	2189 <h4 <%=heading_options%> ><a name="Luan.set_metatable"><tt>Luan.set_metatable (table, metatable)</tt></a></h4>
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2190
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2191 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2192 Sets the metatable for the given table.
475 7ac0891718eb documentation Franklin Schmidt <fschmidt@gmail.com> parents: 474 diff changeset	2193 If <tt>metatable</tt> is <b>nil</b>,
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2194 removes the metatable of the given table.
475 7ac0891718eb documentation Franklin Schmidt <fschmidt@gmail.com> parents: 474 diff changeset	2195 If the original metatable has a <tt>"__metatable"</tt> field,
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2196 raises an error.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2197
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2198
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2199
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2200
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2201 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2202 <hr><h3><a name="pdf-tonumber"><code>tonumber (e [, base])</code></a></h3>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2203
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2204
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2205 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2206 When called with no <code>base</code>,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2207 <code>tonumber</code> tries to convert its argument to a number.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2208 If the argument is already a number or
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2209 a string convertible to a number,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2210 then <code>tonumber</code> returns this number;
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2211 otherwise, it returns <b>nil</b>.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2212
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2213
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2214 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2215 The conversion of strings can result in integers or floats,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2216 according to the lexical conventions of Lua (see <a href="#3.1">§3.1</a>).
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2217 (The string may have leading and trailing spaces and a sign.)
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2218
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2219
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2220 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2221 When called with <code>base</code>,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2222 then <code>e</code> must be a string to be interpreted as
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2223 an integer numeral in that base.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2224 The base may be any integer between 2 and 36, inclusive.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2225 In bases above 10, the letter '<code>A</code>' (in either upper or lower case)
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2226 represents 10, '<code>B</code>' represents 11, and so forth,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2227 with '<code>Z</code>' representing 35.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2228 If the string <code>e</code> is not a valid numeral in the given base,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2229 the function returns <b>nil</b>.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2230
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2231
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2232
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2233
479 1285c52ea9d4 add manual heading_options Franklin Schmidt <fschmidt@gmail.com> parents: 478 diff changeset	2234 <h4 <%=heading_options%> ><a name="Luan.to_string"><tt>Luan.to_string (v)</tt></a></h4>
475 7ac0891718eb documentation Franklin Schmidt <fschmidt@gmail.com> parents: 474 diff changeset	2235
7ac0891718eb documentation Franklin Schmidt <fschmidt@gmail.com> parents: 474 diff changeset	2236 <p>
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2237 Receives a value of any type and
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2238 converts it to a string in a human-readable format.
475 7ac0891718eb documentation Franklin Schmidt <fschmidt@gmail.com> parents: 474 diff changeset	2239
7ac0891718eb documentation Franklin Schmidt <fschmidt@gmail.com> parents: 474 diff changeset	2240 <p>
7ac0891718eb documentation Franklin Schmidt <fschmidt@gmail.com> parents: 474 diff changeset	2241 If the metatable of <tt>v</tt> has a <tt>"__to_string"</tt> field,
7ac0891718eb documentation Franklin Schmidt <fschmidt@gmail.com> parents: 474 diff changeset	2242 then <tt>to_string</tt> calls the corresponding value
7ac0891718eb documentation Franklin Schmidt <fschmidt@gmail.com> parents: 474 diff changeset	2243 with <tt>v</tt> as argument,
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2244 and uses the result of the call as its result.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2245
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2246
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2247
479 1285c52ea9d4 add manual heading_options Franklin Schmidt <fschmidt@gmail.com> parents: 478 diff changeset	2248 <h4 <%=heading_options%> ><a name="Luan.try"><tt>Luan.try (t)</tt></a></h4>
476 cd22e4694ea3 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 475 diff changeset	2249
cd22e4694ea3 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 475 diff changeset	2250 <p>
490 ddee9f5167d8 minor documentation Franklin Schmidt <fschmidt@gmail.com> parents: 482 diff changeset	2251 Implements try-catch as found in other languages where each block is in table <tt>t</tt>. <tt>t[1]</tt> is the "try" block. The <tt>t.catch</tt> and <tt>t.finally</tt> blocks are optional. Returns the result of the "try" block or the "catch" block.
476 cd22e4694ea3 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 475 diff changeset	2252
cd22e4694ea3 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 475 diff changeset	2253 <p>
cd22e4694ea3 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 475 diff changeset	2254 Example use:
cd22e4694ea3 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 475 diff changeset	2255
cd22e4694ea3 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 475 diff changeset	2256 <p><tt><pre>
cd22e4694ea3 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 475 diff changeset	2257 try {
cd22e4694ea3 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 475 diff changeset	2258 function()
cd22e4694ea3 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 475 diff changeset	2259 a_dangerous_fn()
cd22e4694ea3 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 475 diff changeset	2260 end;
cd22e4694ea3 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 475 diff changeset	2261 catch = function(e)
cd22e4694ea3 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 475 diff changeset	2262 -- handle error
cd22e4694ea3 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 475 diff changeset	2263 end;
cd22e4694ea3 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 475 diff changeset	2264 finally = function()
cd22e4694ea3 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 475 diff changeset	2265 -- clean up
cd22e4694ea3 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 475 diff changeset	2266 end;
cd22e4694ea3 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 475 diff changeset	2267 }
cd22e4694ea3 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 475 diff changeset	2268 </pre></tt></p>
cd22e4694ea3 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 475 diff changeset	2269
482 7e9fcfbf22ec documentation Franklin Schmidt <fschmidt@gmail.com> parents: 479 diff changeset	2270 <p>
7e9fcfbf22ec documentation Franklin Schmidt <fschmidt@gmail.com> parents: 479 diff changeset	2271 Could be defined as:
7e9fcfbf22ec documentation Franklin Schmidt <fschmidt@gmail.com> parents: 479 diff changeset	2272
7e9fcfbf22ec documentation Franklin Schmidt <fschmidt@gmail.com> parents: 479 diff changeset	2273 <p><tt><pre>
7e9fcfbf22ec documentation Franklin Schmidt <fschmidt@gmail.com> parents: 479 diff changeset	2274 function Luan.try(t)
7e9fcfbf22ec documentation Franklin Schmidt <fschmidt@gmail.com> parents: 479 diff changeset	2275 local r = { <a href="#Luan.pcall">Luan.pcall</a>(t[1]) }
7e9fcfbf22ec documentation Franklin Schmidt <fschmidt@gmail.com> parents: 479 diff changeset	2276 if r[1] then
7e9fcfbf22ec documentation Franklin Schmidt <fschmidt@gmail.com> parents: 479 diff changeset	2277 Table.remove(r,1)
7e9fcfbf22ec documentation Franklin Schmidt <fschmidt@gmail.com> parents: 479 diff changeset	2278 elseif t.catch ~= nil then
7e9fcfbf22ec documentation Franklin Schmidt <fschmidt@gmail.com> parents: 479 diff changeset	2279 r = { t.catch(r[2]) }
7e9fcfbf22ec documentation Franklin Schmidt <fschmidt@gmail.com> parents: 479 diff changeset	2280 else
7e9fcfbf22ec documentation Franklin Schmidt <fschmidt@gmail.com> parents: 479 diff changeset	2281 t.finally and t.finally()
7e9fcfbf22ec documentation Franklin Schmidt <fschmidt@gmail.com> parents: 479 diff changeset	2282 r[2].throw()
7e9fcfbf22ec documentation Franklin Schmidt <fschmidt@gmail.com> parents: 479 diff changeset	2283 end
7e9fcfbf22ec documentation Franklin Schmidt <fschmidt@gmail.com> parents: 479 diff changeset	2284 t.finally and t.finally()
7e9fcfbf22ec documentation Franklin Schmidt <fschmidt@gmail.com> parents: 479 diff changeset	2285 return Table.unpack(r)
7e9fcfbf22ec documentation Franklin Schmidt <fschmidt@gmail.com> parents: 479 diff changeset	2286 end
7e9fcfbf22ec documentation Franklin Schmidt <fschmidt@gmail.com> parents: 479 diff changeset	2287 </pre></tt></p>
476 cd22e4694ea3 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 475 diff changeset	2288
cd22e4694ea3 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 475 diff changeset	2289
479 1285c52ea9d4 add manual heading_options Franklin Schmidt <fschmidt@gmail.com> parents: 478 diff changeset	2290 <h4 <%=heading_options%> ><a name="Luan.type"><tt>Luan.type (v)</tt></a></h4>
475 7ac0891718eb documentation Franklin Schmidt <fschmidt@gmail.com> parents: 474 diff changeset	2291
7ac0891718eb documentation Franklin Schmidt <fschmidt@gmail.com> parents: 474 diff changeset	2292 <p>
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2293 Returns the type of its only argument, coded as a string.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2294 The possible results of this function are
475 7ac0891718eb documentation Franklin Schmidt <fschmidt@gmail.com> parents: 474 diff changeset	2295 "<tt>nil</tt>" (a string, not the value <b>nil</b>),
7ac0891718eb documentation Franklin Schmidt <fschmidt@gmail.com> parents: 474 diff changeset	2296 "<tt>number</tt>",
7ac0891718eb documentation Franklin Schmidt <fschmidt@gmail.com> parents: 474 diff changeset	2297 "<tt>string</tt>",
7ac0891718eb documentation Franklin Schmidt <fschmidt@gmail.com> parents: 474 diff changeset	2298 "<tt>binary</tt>",
7ac0891718eb documentation Franklin Schmidt <fschmidt@gmail.com> parents: 474 diff changeset	2299 "<tt>boolean</tt>",
7ac0891718eb documentation Franklin Schmidt <fschmidt@gmail.com> parents: 474 diff changeset	2300 "<tt>table</tt>",
7ac0891718eb documentation Franklin Schmidt <fschmidt@gmail.com> parents: 474 diff changeset	2301 "<tt>function</tt>",
7ac0891718eb documentation Franklin Schmidt <fschmidt@gmail.com> parents: 474 diff changeset	2302 and "<tt>userdata</tt>".
7ac0891718eb documentation Franklin Schmidt <fschmidt@gmail.com> parents: 474 diff changeset	2303
7ac0891718eb documentation Franklin Schmidt <fschmidt@gmail.com> parents: 474 diff changeset	2304
479 1285c52ea9d4 add manual heading_options Franklin Schmidt <fschmidt@gmail.com> parents: 478 diff changeset	2305 <h4 <%=heading_options%> ><a name="Luan.values"><tt>Luan.values (···)</tt></a></h4>
476 cd22e4694ea3 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 475 diff changeset	2306
cd22e4694ea3 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 475 diff changeset	2307 <p>
cd22e4694ea3 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 475 diff changeset	2308 Returns a function so that the construction
cd22e4694ea3 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 475 diff changeset	2309
cd22e4694ea3 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 475 diff changeset	2310 <p><tt><pre>
cd22e4694ea3 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 475 diff changeset	2311 for v in Luan.values(···) do <i>body</i> end
cd22e4694ea3 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 475 diff changeset	2312 </pre></tt></p>
cd22e4694ea3 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 475 diff changeset	2313
cd22e4694ea3 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 475 diff changeset	2314 <p>
cd22e4694ea3 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 475 diff changeset	2315 will iterate over all values of <tt>···</tt>.
cd22e4694ea3 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 475 diff changeset	2316
cd22e4694ea3 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 475 diff changeset	2317
475 7ac0891718eb documentation Franklin Schmidt <fschmidt@gmail.com> parents: 474 diff changeset	2318
479 1285c52ea9d4 add manual heading_options Franklin Schmidt <fschmidt@gmail.com> parents: 478 diff changeset	2319 <h4 <%=heading_options%> ><a name="Luan.VERSION"><tt>Luan.VERSION</tt></a></h4>
475 7ac0891718eb documentation Franklin Schmidt <fschmidt@gmail.com> parents: 474 diff changeset	2320
7ac0891718eb documentation Franklin Schmidt <fschmidt@gmail.com> parents: 474 diff changeset	2321 <p>
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2322 A global variable (not a function) that
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2323 holds a string containing the current interpreter version.
478 eb6d90fb0b5c documentation Franklin Schmidt <fschmidt@gmail.com> parents: 476 diff changeset	2324 The current value of this variable is "<tt><%=Luan.VERSION%></tt>".
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2325
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2326
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2327
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2328
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2329
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2330
479 1285c52ea9d4 add manual heading_options Franklin Schmidt <fschmidt@gmail.com> parents: 478 diff changeset	2331 <h3 <%=heading_options%> ><a name="package_lib">Modules</a></h3>
476 cd22e4694ea3 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 475 diff changeset	2332
cd22e4694ea3 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 475 diff changeset	2333 <p>
cd22e4694ea3 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 475 diff changeset	2334 Include this library by:
cd22e4694ea3 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 475 diff changeset	2335
cd22e4694ea3 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 475 diff changeset	2336 <p><tt><pre>
cd22e4694ea3 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 475 diff changeset	2337 local Package = require "luan:Package"
cd22e4694ea3 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 475 diff changeset	2338 </pre></tt></p>
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2339
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2340 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2341 The package library provides basic
476 cd22e4694ea3 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 475 diff changeset	2342 facilities for loading modules in Luan.
cd22e4694ea3 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 475 diff changeset	2343
cd22e4694ea3 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 475 diff changeset	2344
479 1285c52ea9d4 add manual heading_options Franklin Schmidt <fschmidt@gmail.com> parents: 478 diff changeset	2345 <h4 <%=heading_options%> ><a name="Package.load"><tt>Package.load (mod_uri)</tt></a></h4>
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2346
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2347 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2348 Loads the given module.
476 cd22e4694ea3 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 475 diff changeset	2349 The function starts by looking into the <a href="#Package.loaded"><tt>Package.loaded</tt></a> table
cd22e4694ea3 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 475 diff changeset	2350 to determine whether <tt>mod_uri</tt> is already loaded.
cd22e4694ea3 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 475 diff changeset	2351 If it is, then <tt>Package.load</tt> returns the value stored
cd22e4694ea3 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 475 diff changeset	2352 at <tt>Package.loaded[mod_uri]</tt>.
cd22e4694ea3 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 475 diff changeset	2353 Otherwise, it tries to load a new value for the module.
cd22e4694ea3 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 475 diff changeset	2354
cd22e4694ea3 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 475 diff changeset	2355 <p>
cd22e4694ea3 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 475 diff changeset	2356 To load a new value, <tt>Package.load</tt> first checks if <tt>mod_uri</tt> starts with "<b>java:</b>". If yes, then this is a Java class which is loaded by special Java code.
cd22e4694ea3 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 475 diff changeset	2357
cd22e4694ea3 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 475 diff changeset	2358 <p>
cd22e4694ea3 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 475 diff changeset	2359 If <tt>mod_uri</tt> is not a Java class, then <tt>Package.load</tt> tries to read the text of the file referred to by <tt>mod_uri</tt> (using <tt>add_extension</tt>=true). If the file doesn't exist, then <tt>Package.load</tt> returns <b>nil</b>. If the file exists, then its content is compiled into a chunk calling <a href="#Luan.load"><tt>Luan.load</tt></a> and passing in an empty table as the <tt>env</tt> value. This chunk is run passing in <tt>mod_uri</tt> as an argument. If the chunk returns a value other than <b>nil</b>, then that value is the value of this module. Otherwise the <tt>env</tt> that was passed in is the value of this module.
cd22e4694ea3 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 475 diff changeset	2360
cd22e4694ea3 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 475 diff changeset	2361 <p>
cd22e4694ea3 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 475 diff changeset	2362 If a new value for the module successful loaded, then it is stored in <tt>Package.loaded[mod_uri]</tt>. The value is returned.
cd22e4694ea3 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 475 diff changeset	2363
cd22e4694ea3 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 475 diff changeset	2364
cd22e4694ea3 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 475 diff changeset	2365
cd22e4694ea3 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 475 diff changeset	2366
479 1285c52ea9d4 add manual heading_options Franklin Schmidt <fschmidt@gmail.com> parents: 478 diff changeset	2367 <h4 <%=heading_options%> ><a name="Package.loaded"><tt>Package.loaded</tt></a></h4>
476 cd22e4694ea3 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 475 diff changeset	2368
cd22e4694ea3 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 475 diff changeset	2369
cd22e4694ea3 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 475 diff changeset	2370 <p>
cd22e4694ea3 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 475 diff changeset	2371 A table used by <a href="#Package.load"><tt>Package.load</tt></a> to control which
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2372 modules are already loaded.
476 cd22e4694ea3 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 475 diff changeset	2373 When you load a module <tt>mod_uri</tt> and
cd22e4694ea3 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 475 diff changeset	2374 <tt>Package.loaded[modname]</tt> is not <b>nil</b>,
cd22e4694ea3 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 475 diff changeset	2375 <a href="#Package.load"><tt>Package.load</tt></a> simply returns the value stored there.
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2376
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2377
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2378 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2379 This variable is only a reference to the real table;
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2380 assignments to this variable do not change the
476 cd22e4694ea3 documentation Franklin Schmidt <fschmidt@gmail.com> parents: 475 diff changeset	2381 table used by <a href="#Package.load"><tt>Package.load</tt></a>.
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2382
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2383
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2384
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2385
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2386
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2387
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2388 <h2>6.4 – <a name="6.4">String Manipulation</a></h2>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2389
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2390 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2391 This library provides generic functions for string manipulation,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2392 such as finding and extracting substrings, and pattern matching.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2393 When indexing a string in Lua, the first character is at position 1
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2394 (not at 0, as in C).
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2395 Indices are allowed to be negative and are interpreted as indexing backwards,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2396 from the end of the string.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2397 Thus, the last character is at position -1, and so on.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2398
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2399
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2400 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2401 The string library provides all its functions inside the table
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2402 <a name="pdf-string"><code>string</code></a>.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2403 It also sets a metatable for strings
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2404 where the <code>__index</code> field points to the <code>string</code> table.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2405 Therefore, you can use the string functions in object-oriented style.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2406 For instance, <code>string.byte(s,i)</code>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2407 can be written as <code>s:byte(i)</code>.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2408
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2409
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2410 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2411 The string library assumes one-byte character encodings.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2412
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2413
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2414 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2415 <hr><h3><a name="pdf-string.byte"><code>string.byte (s [, i [, j]])</code></a></h3>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2416 Returns the internal numerical codes of the characters <code>s[i]</code>,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2417 <code>s[i+1]</code>, ..., <code>s[j]</code>.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2418 The default value for <code>i</code> is 1;
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2419 the default value for <code>j</code> is <code>i</code>.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2420 These indices are corrected
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2421 following the same rules of function <a href="#pdf-string.sub"><code>string.sub</code></a>.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2422
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2423
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2424 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2425 Numerical codes are not necessarily portable across platforms.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2426
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2427
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2428
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2429
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2430 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2431 <hr><h3><a name="pdf-string.char"><code>string.char (···)</code></a></h3>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2432 Receives zero or more integers.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2433 Returns a string with length equal to the number of arguments,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2434 in which each character has the internal numerical code equal
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2435 to its corresponding argument.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2436
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2437
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2438 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2439 Numerical codes are not necessarily portable across platforms.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2440
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2441
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2442
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2443
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2444 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2445 <hr><h3><a name="pdf-string.dump"><code>string.dump (function [, strip])</code></a></h3>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2446
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2447
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2448 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2449 Returns a string containing a binary representation
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2450 (a <em>binary chunk</em>)
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2451 of the given function,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2452 so that a later <a href="#pdf-load"><code>load</code></a> on this string returns
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2453 a copy of the function (but with new upvalues).
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2454 If <code>strip</code> is a true value,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2455 the binary representation is created without debug information
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2456 about the function
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2457 (local variable names, lines, etc.).
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2458
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2459
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2460 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2461 Functions with upvalues have only their number of upvalues saved.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2462 When (re)loaded,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2463 those upvalues receive fresh instances containing <b>nil</b>.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2464 (You can use the debug library to serialize
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2465 and reload the upvalues of a function
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2466 in a way adequate to your needs.)
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2467
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2468
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2469
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2470
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2471 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2472 <hr><h3><a name="pdf-string.find"><code>string.find (s, pattern [, init [, plain]])</code></a></h3>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2473
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2474
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2475 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2476 Looks for the first match of
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2477 <code>pattern</code> (see <a href="#6.4.1">§6.4.1</a>) in the string <code>s</code>.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2478 If it finds a match, then <code>find</code> returns the indices of <code>s</code>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2479 where this occurrence starts and ends;
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2480 otherwise, it returns <b>nil</b>.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2481 A third, optional numerical argument <code>init</code> specifies
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2482 where to start the search;
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2483 its default value is 1 and can be negative.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2484 A value of <b>true</b> as a fourth, optional argument <code>plain</code>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2485 turns off the pattern matching facilities,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2486 so the function does a plain "find substring" operation,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2487 with no characters in <code>pattern</code> being considered magic.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2488 Note that if <code>plain</code> is given, then <code>init</code> must be given as well.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2489
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2490
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2491 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2492 If the pattern has captures,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2493 then in a successful match
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2494 the captured values are also returned,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2495 after the two indices.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2496
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2497
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2498
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2499
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2500 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2501 <hr><h3><a name="pdf-string.format"><code>string.format (formatstring, ···)</code></a></h3>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2502
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2503
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2504 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2505 Returns a formatted version of its variable number of arguments
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2506 following the description given in its first argument (which must be a string).
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2507 The format string follows the same rules as the ISO C function <code>sprintf</code>.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2508 The only differences are that the options/modifiers
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2509 <code>*</code>, <code>h</code>, <code>L</code>, <code>l</code>, <code>n</code>,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2510 and <code>p</code> are not supported
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2511 and that there is an extra option, <code>q</code>.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2512 The <code>q</code> option formats a string between double quotes,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2513 using escape sequences when necessary to ensure that
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2514 it can safely be read back by the Lua interpreter.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2515 For instance, the call
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2516
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2517 <pre>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2518 string.format('%q', 'a string with "quotes" and \n new line')
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2519 </pre><p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2520 may produce the string:
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2521
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2522 <pre>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2523 "a string with \"quotes\" and \
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2524 new line"
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2525 </pre>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2526
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2527 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2528 Options
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2529 <code>A</code> and <code>a</code> (when available),
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2530 <code>E</code>, <code>e</code>, <code>f</code>,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2531 <code>G</code>, and <code>g</code> all expect a number as argument.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2532 Options <code>c</code>, <code>d</code>,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2533 <code>i</code>, <code>o</code>, <code>u</code>, <code>X</code>, and <code>x</code>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2534 expect an integer.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2535 Option <code>q</code> expects a string;
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2536 option <code>s</code> expects a string without embedded zeros.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2537 If the argument to option <code>s</code> is not a string,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2538 it is converted to one following the same rules of <a href="#pdf-tostring"><code>tostring</code></a>.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2539
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2540
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2541
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2542
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2543 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2544 <hr><h3><a name="pdf-string.gmatch"><code>string.gmatch (s, pattern)</code></a></h3>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2545 Returns an iterator function that,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2546 each time it is called,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2547 returns the next captures from <code>pattern</code> (see <a href="#6.4.1">§6.4.1</a>)
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2548 over the string <code>s</code>.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2549 If <code>pattern</code> specifies no captures,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2550 then the whole match is produced in each call.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2551
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2552
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2553 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2554 As an example, the following loop
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2555 will iterate over all the words from string <code>s</code>,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2556 printing one per line:
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2557
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2558 <pre>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2559 s = "hello world from Lua"
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2560 for w in string.gmatch(s, "%a+") do
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2561 print(w)
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2562 end
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2563 </pre><p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2564 The next example collects all pairs <code>key=value</code> from the
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2565 given string into a table:
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2566
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2567 <pre>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2568 t = {}
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2569 s = "from=world, to=Lua"
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2570 for k, v in string.gmatch(s, "(%w+)=(%w+)") do
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2571 t[k] = v
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2572 end
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2573 </pre>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2574
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2575 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2576 For this function, a caret '<code>^</code>' at the start of a pattern does not
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2577 work as an anchor, as this would prevent the iteration.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2578
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2579
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2580
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2581
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2582 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2583 <hr><h3><a name="pdf-string.gsub"><code>string.gsub (s, pattern, repl [, n])</code></a></h3>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2584 Returns a copy of <code>s</code>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2585 in which all (or the first <code>n</code>, if given)
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2586 occurrences of the <code>pattern</code> (see <a href="#6.4.1">§6.4.1</a>) have been
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2587 replaced by a replacement string specified by <code>repl</code>,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2588 which can be a string, a table, or a function.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2589 <code>gsub</code> also returns, as its second value,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2590 the total number of matches that occurred.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2591 The name <code>gsub</code> comes from <em>Global SUBstitution</em>.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2592
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2593
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2594 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2595 If <code>repl</code> is a string, then its value is used for replacement.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2596 The character <code>%</code> works as an escape character:
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2597 any sequence in <code>repl</code> of the form <code>%<em>d</em></code>,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2598 with <em>d</em> between 1 and 9,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2599 stands for the value of the <em>d</em>-th captured substring.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2600 The sequence <code>%0</code> stands for the whole match.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2601 The sequence <code>%%</code> stands for a single <code>%</code>.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2602
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2603
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2604 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2605 If <code>repl</code> is a table, then the table is queried for every match,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2606 using the first capture as the key.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2607
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2608
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2609 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2610 If <code>repl</code> is a function, then this function is called every time a
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2611 match occurs, with all captured substrings passed as arguments,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2612 in order.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2613
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2614
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2615 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2616 In any case,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2617 if the pattern specifies no captures,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2618 then it behaves as if the whole pattern was inside a capture.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2619
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2620
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2621 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2622 If the value returned by the table query or by the function call
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2623 is a string or a number,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2624 then it is used as the replacement string;
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2625 otherwise, if it is <b>false</b> or <b>nil</b>,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2626 then there is no replacement
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2627 (that is, the original match is kept in the string).
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2628
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2629
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2630 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2631 Here are some examples:
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2632
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2633 <pre>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2634 x = string.gsub("hello world", "(%w+)", "%1 %1")
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2635 --> x="hello hello world world"
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2636
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2637 x = string.gsub("hello world", "%w+", "%0 %0", 1)
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2638 --> x="hello hello world"
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2639
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2640 x = string.gsub("hello world from Lua", "(%w+)%s*(%w+)", "%2 %1")
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2641 --> x="world hello Lua from"
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2642
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2643 x = string.gsub("home = $HOME, user = $USER", "%$(%w+)", os.getenv)
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2644 --> x="home = /home/roberto, user = roberto"
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2645
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2646 x = string.gsub("4+5 = $return 4+5$", "%$(.-)%$", function (s)
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2647 return load(s)()
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2648 end)
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2649 --> x="4+5 = 9"
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2650
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2651 local t = {name="lua", version="5.3"}
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2652 x = string.gsub("$name-$version.tar.gz", "%$(%w+)", t)
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2653 --> x="lua-5.3.tar.gz"
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2654 </pre>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2655
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2656
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2657
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2658 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2659 <hr><h3><a name="pdf-string.len"><code>string.len (s)</code></a></h3>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2660 Receives a string and returns its length.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2661 The empty string <code>""</code> has length 0.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2662 Embedded zeros are counted,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2663 so <code>"a\000bc\000"</code> has length 5.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2664
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2665
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2666
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2667
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2668 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2669 <hr><h3><a name="pdf-string.lower"><code>string.lower (s)</code></a></h3>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2670 Receives a string and returns a copy of this string with all
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2671 uppercase letters changed to lowercase.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2672 All other characters are left unchanged.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2673 The definition of what an uppercase letter is depends on the current locale.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2674
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2675
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2676
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2677
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2678 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2679 <hr><h3><a name="pdf-string.match"><code>string.match (s, pattern [, init])</code></a></h3>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2680 Looks for the first <em>match</em> of
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2681 <code>pattern</code> (see <a href="#6.4.1">§6.4.1</a>) in the string <code>s</code>.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2682 If it finds one, then <code>match</code> returns
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2683 the captures from the pattern;
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2684 otherwise it returns <b>nil</b>.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2685 If <code>pattern</code> specifies no captures,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2686 then the whole match is returned.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2687 A third, optional numerical argument <code>init</code> specifies
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2688 where to start the search;
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2689 its default value is 1 and can be negative.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2690
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2691
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2692
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2693
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2694 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2695 <hr><h3><a name="pdf-string.pack"><code>string.pack (fmt, v1, v2, ···)</code></a></h3>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2696
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2697
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2698 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2699 Returns a binary string containing the values <code>v1</code>, <code>v2</code>, etc.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2700 packed (that is, serialized in binary form)
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2701 according to the format string <code>fmt</code> (see <a href="#6.4.2">§6.4.2</a>).
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2702
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2703
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2704
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2705
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2706 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2707 <hr><h3><a name="pdf-string.packsize"><code>string.packsize (fmt)</code></a></h3>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2708
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2709
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2710 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2711 Returns the size of a string resulting from <a href="#pdf-string.pack"><code>string.pack</code></a>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2712 with the given format.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2713 The format string cannot have the variable-length options
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2714 '<code>s</code>' or '<code>z</code>' (see <a href="#6.4.2">§6.4.2</a>).
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2715
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2716
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2717
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2718
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2719 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2720 <hr><h3><a name="pdf-string.rep"><code>string.rep (s, n [, sep])</code></a></h3>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2721 Returns a string that is the concatenation of <code>n</code> copies of
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2722 the string <code>s</code> separated by the string <code>sep</code>.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2723 The default value for <code>sep</code> is the empty string
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2724 (that is, no separator).
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2725 Returns the empty string if <code>n</code> is not positive.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2726
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2727
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2728
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2729
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2730 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2731 <hr><h3><a name="pdf-string.reverse"><code>string.reverse (s)</code></a></h3>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2732 Returns a string that is the string <code>s</code> reversed.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2733
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2734
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2735
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2736
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2737 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2738 <hr><h3><a name="pdf-string.sub"><code>string.sub (s, i [, j])</code></a></h3>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2739 Returns the substring of <code>s</code> that
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2740 starts at <code>i</code> and continues until <code>j</code>;
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2741 <code>i</code> and <code>j</code> can be negative.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2742 If <code>j</code> is absent, then it is assumed to be equal to -1
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2743 (which is the same as the string length).
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2744 In particular,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2745 the call <code>string.sub(s,1,j)</code> returns a prefix of <code>s</code>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2746 with length <code>j</code>,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2747 and <code>string.sub(s, -i)</code> returns a suffix of <code>s</code>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2748 with length <code>i</code>.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2749
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2750
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2751 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2752 If, after the translation of negative indices,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2753 <code>i</code> is less than 1,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2754 it is corrected to 1.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2755 If <code>j</code> is greater than the string length,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2756 it is corrected to that length.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2757 If, after these corrections,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2758 <code>i</code> is greater than <code>j</code>,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2759 the function returns the empty string.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2760
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2761
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2762
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2763
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2764 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2765 <hr><h3><a name="pdf-string.unpack"><code>string.unpack (fmt, s [, pos])</code></a></h3>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2766
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2767
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2768 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2769 Returns the values packed in string <code>s</code> (see <a href="#pdf-string.pack"><code>string.pack</code></a>)
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2770 according to the format string <code>fmt</code> (see <a href="#6.4.2">§6.4.2</a>).
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2771 An optional <code>pos</code> marks where
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2772 to start reading in <code>s</code> (default is 1).
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2773 After the read values,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2774 this function also returns the index of the first unread byte in <code>s</code>.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2775
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2776
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2777
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2778
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2779 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2780 <hr><h3><a name="pdf-string.upper"><code>string.upper (s)</code></a></h3>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2781 Receives a string and returns a copy of this string with all
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2782 lowercase letters changed to uppercase.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2783 All other characters are left unchanged.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2784 The definition of what a lowercase letter is depends on the current locale.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2785
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2786
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2787
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2788
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2789
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2790 <h3>6.4.1 – <a name="6.4.1">Patterns</a></h3>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2791
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2792 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2793 Patterns in Lua are described by regular strings,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2794 which are interpreted as patterns by the pattern-matching functions
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2795 <a href="#pdf-string.find"><code>string.find</code></a>,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2796 <a href="#pdf-string.gmatch"><code>string.gmatch</code></a>,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2797 <a href="#pdf-string.gsub"><code>string.gsub</code></a>,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2798 and <a href="#pdf-string.match"><code>string.match</code></a>.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2799 This section describes the syntax and the meaning
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2800 (that is, what they match) of these strings.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2801
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2802
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2803
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2804 <h4>Character Class:</h4><p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2805 A <em>character class</em> is used to represent a set of characters.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2806 The following combinations are allowed in describing a character class:
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2807
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2808 <ul>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2809
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2810 <li><b><em>x</em>: </b>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2811 (where <em>x</em> is not one of the <em>magic characters</em>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2812 <code>^$()%.[]*+-?</code>)
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2813 represents the character <em>x</em> itself.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2814 </li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2815
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2816 <li><b><code>.</code>: </b> (a dot) represents all characters.</li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2817
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2818 <li><b><code>%a</code>: </b> represents all letters.</li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2819
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2820 <li><b><code>%c</code>: </b> represents all control characters.</li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2821
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2822 <li><b><code>%d</code>: </b> represents all digits.</li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2823
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2824 <li><b><code>%g</code>: </b> represents all printable characters except space.</li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2825
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2826 <li><b><code>%l</code>: </b> represents all lowercase letters.</li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2827
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2828 <li><b><code>%p</code>: </b> represents all punctuation characters.</li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2829
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2830 <li><b><code>%s</code>: </b> represents all space characters.</li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2831
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2832 <li><b><code>%u</code>: </b> represents all uppercase letters.</li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2833
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2834 <li><b><code>%w</code>: </b> represents all alphanumeric characters.</li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2835
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2836 <li><b><code>%x</code>: </b> represents all hexadecimal digits.</li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2837
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2838 <li><b><code>%<em>x</em></code>: </b> (where <em>x</em> is any non-alphanumeric character)
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2839 represents the character <em>x</em>.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2840 This is the standard way to escape the magic characters.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2841 Any non-alphanumeric character
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2842 (including all punctuations, even the non-magical)
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2843 can be preceded by a '<code>%</code>'
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2844 when used to represent itself in a pattern.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2845 </li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2846
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2847 <li><b><code>[<em>set</em>]</code>: </b>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2848 represents the class which is the union of all
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2849 characters in <em>set</em>.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2850 A range of characters can be specified by
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2851 separating the end characters of the range,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2852 in ascending order, with a '<code>-</code>'.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2853 All classes <code>%</code><em>x</em> described above can also be used as
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2854 components in <em>set</em>.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2855 All other characters in <em>set</em> represent themselves.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2856 For example, <code>[%w_]</code> (or <code>[_%w]</code>)
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2857 represents all alphanumeric characters plus the underscore,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2858 <code>[0-7]</code> represents the octal digits,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2859 and <code>[0-7%l%-]</code> represents the octal digits plus
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2860 the lowercase letters plus the '<code>-</code>' character.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2861
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2862
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2863 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2864 The interaction between ranges and classes is not defined.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2865 Therefore, patterns like <code>[%a-z]</code> or <code>[a-%%]</code>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2866 have no meaning.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2867 </li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2868
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2869 <li><b><code>[^<em>set</em>]</code>: </b>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2870 represents the complement of <em>set</em>,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2871 where <em>set</em> is interpreted as above.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2872 </li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2873
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2874 </ul><p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2875 For all classes represented by single letters (<code>%a</code>, <code>%c</code>, etc.),
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2876 the corresponding uppercase letter represents the complement of the class.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2877 For instance, <code>%S</code> represents all non-space characters.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2878
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2879
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2880 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2881 The definitions of letter, space, and other character groups
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2882 depend on the current locale.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2883 In particular, the class <code>[a-z]</code> may not be equivalent to <code>%l</code>.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2884
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2885
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2886
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2887
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2888
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2889 <h4>Pattern Item:</h4><p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2890 A <em>pattern item</em> can be
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2891
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2892 <ul>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2893
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2894 <li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2895 a single character class,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2896 which matches any single character in the class;
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2897 </li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2898
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2899 <li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2900 a single character class followed by '<code>*</code>',
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2901 which matches zero or more repetitions of characters in the class.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2902 These repetition items will always match the longest possible sequence;
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2903 </li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2904
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2905 <li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2906 a single character class followed by '<code>+</code>',
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2907 which matches one or more repetitions of characters in the class.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2908 These repetition items will always match the longest possible sequence;
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2909 </li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2910
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2911 <li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2912 a single character class followed by '<code>-</code>',
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2913 which also matches zero or more repetitions of characters in the class.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2914 Unlike '<code>*</code>',
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2915 these repetition items will always match the shortest possible sequence;
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2916 </li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2917
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2918 <li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2919 a single character class followed by '<code>?</code>',
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2920 which matches zero or one occurrence of a character in the class.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2921 It always matches one occurrence if possible;
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2922 </li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2923
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2924 <li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2925 <code>%<em>n</em></code>, for <em>n</em> between 1 and 9;
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2926 such item matches a substring equal to the <em>n</em>-th captured string
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2927 (see below);
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2928 </li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2929
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2930 <li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2931 <code>%b<em>xy</em></code>, where <em>x</em> and <em>y</em> are two distinct characters;
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2932 such item matches strings that start with <em>x</em>, end with <em>y</em>,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2933 and where the <em>x</em> and <em>y</em> are <em>balanced</em>.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2934 This means that, if one reads the string from left to right,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2935 counting <em>+1</em> for an <em>x</em> and <em>-1</em> for a <em>y</em>,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2936 the ending <em>y</em> is the first <em>y</em> where the count reaches 0.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2937 For instance, the item <code>%b()</code> matches expressions with
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2938 balanced parentheses.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2939 </li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2940
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2941 <li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2942 <code>%f[<em>set</em>]</code>, a <em>frontier pattern</em>;
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2943 such item matches an empty string at any position such that
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2944 the next character belongs to <em>set</em>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2945 and the previous character does not belong to <em>set</em>.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2946 The set <em>set</em> is interpreted as previously described.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2947 The beginning and the end of the subject are handled as if
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2948 they were the character '<code>\0</code>'.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2949 </li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2950
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2951 </ul>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2952
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2953
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2954
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2955
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2956 <h4>Pattern:</h4><p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2957 A <em>pattern</em> is a sequence of pattern items.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2958 A caret '<code>^</code>' at the beginning of a pattern anchors the match at the
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2959 beginning of the subject string.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2960 A '<code>$</code>' at the end of a pattern anchors the match at the
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2961 end of the subject string.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2962 At other positions,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2963 '<code>^</code>' and '<code>$</code>' have no special meaning and represent themselves.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2964
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2965
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2966
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2967
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2968
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2969 <h4>Captures:</h4><p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2970 A pattern can contain sub-patterns enclosed in parentheses;
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2971 they describe <em>captures</em>.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2972 When a match succeeds, the substrings of the subject string
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2973 that match captures are stored (<em>captured</em>) for future use.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2974 Captures are numbered according to their left parentheses.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2975 For instance, in the pattern <code>"(a(.)%w(%s))"</code>,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2976 the part of the string matching <code>"a(.)%w(%s)"</code> is
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2977 stored as the first capture (and therefore has number 1);
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2978 the character matching "<code>.</code>" is captured with number 2,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2979 and the part matching "<code>%s*</code>" has number 3.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2980
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2981
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2982 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2983 As a special case, the empty capture <code>()</code> captures
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2984 the current string position (a number).
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2985 For instance, if we apply the pattern <code>"()aa()"</code> on the
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2986 string <code>"flaaap"</code>, there will be two captures: 3 and 5.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2987
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2988
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2989
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2990
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2991
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2992
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2993
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2994 <h3>6.4.2 – <a name="6.4.2">Format Strings for Pack and Unpack</a></h3>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2995
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2996 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2997 The first argument to <a href="#pdf-string.pack"><code>string.pack</code></a>,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2998 <a href="#pdf-string.packsize"><code>string.packsize</code></a>, and <a href="#pdf-string.unpack"><code>string.unpack</code></a>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	2999 is a format string,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3000 which describes the layout of the structure being created or read.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3001
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3002
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3003 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3004 A format string is a sequence of conversion options.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3005 The conversion options are as follows:
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3006
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3007 <ul>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3008 <li><b><code><</code>: </b>sets little endian</li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3009 <li><b><code>></code>: </b>sets big endian</li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3010 <li><b><code>=</code>: </b>sets native endian</li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3011 <li><b><code>![<em>n</em>]</code>: </b>sets maximum alignment to <code>n</code>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3012 (default is native alignment)</li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3013 <li><b><code>b</code>: </b>a signed byte (<code>char</code>)</li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3014 <li><b><code>B</code>: </b>an unsigned byte (<code>char</code>)</li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3015 <li><b><code>h</code>: </b>a signed <code>short</code> (native size)</li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3016 <li><b><code>H</code>: </b>an unsigned <code>short</code> (native size)</li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3017 <li><b><code>l</code>: </b>a signed <code>long</code> (native size)</li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3018 <li><b><code>L</code>: </b>an unsigned <code>long</code> (native size)</li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3019 <li><b><code>j</code>: </b>a <code>lua_Integer</code></li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3020 <li><b><code>J</code>: </b>a <code>lua_Unsigned</code></li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3021 <li><b><code>T</code>: </b>a <code>size_t</code> (native size)</li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3022 <li><b><code>i[<em>n</em>]</code>: </b>a signed <code>int</code> with <code>n</code> bytes
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3023 (default is native size)</li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3024 <li><b><code>I[<em>n</em>]</code>: </b>an unsigned <code>int</code> with <code>n</code> bytes
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3025 (default is native size)</li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3026 <li><b><code>f</code>: </b>a <code>float</code> (native size)</li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3027 <li><b><code>d</code>: </b>a <code>double</code> (native size)</li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3028 <li><b><code>n</code>: </b>a <code>lua_Number</code></li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3029 <li><b><code>c<em>n</em></code>: </b>a fixed-sized string with <code>n</code> bytes</li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3030 <li><b><code>z</code>: </b>a zero-terminated string</li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3031 <li><b><code>s[<em>n</em>]</code>: </b>a string preceded by its length
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3032 coded as an unsigned integer with <code>n</code> bytes
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3033 (default is a <code>size_t</code>)</li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3034 <li><b><code>x</code>: </b>one byte of padding</li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3035 <li><b><code>X<em>op</em></code>: </b>an empty item that aligns
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3036 according to option <code>op</code>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3037 (which is otherwise ignored)</li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3038 <li><b>'<code> </code>': </b>(empty space) ignored</li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3039 </ul><p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3040 (A "<code>[<em>n</em>]</code>" means an optional integral numeral.)
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3041 Except for padding, spaces, and configurations
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3042 (options "<code>xX <=>!</code>"),
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3043 each option corresponds to an argument (in <a href="#pdf-string.pack"><code>string.pack</code></a>)
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3044 or a result (in <a href="#pdf-string.unpack"><code>string.unpack</code></a>).
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3045
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3046
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3047 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3048 For options "<code>!<em>n</em></code>", "<code>s<em>n</em></code>", "<code>i<em>n</em></code>", and "<code>I<em>n</em></code>",
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3049 <code>n</code> can be any integer between 1 and 16.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3050 All integral options check overflows;
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3051 <a href="#pdf-string.pack"><code>string.pack</code></a> checks whether the given value fits in the given size;
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3052 <a href="#pdf-string.unpack"><code>string.unpack</code></a> checks whether the read value fits in a Lua integer.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3053
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3054
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3055 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3056 Any format string starts as if prefixed by "<code>!1=</code>",
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3057 that is,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3058 with maximum alignment of 1 (no alignment)
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3059 and native endianness.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3060
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3061
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3062 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3063 Alignment works as follows:
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3064 For each option,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3065 the format gets extra padding until the data starts
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3066 at an offset that is a multiple of the minimum between the
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3067 option size and the maximum alignment;
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3068 this minimum must be a power of 2.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3069 Options "<code>c</code>" and "<code>z</code>" are not aligned;
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3070 option "<code>s</code>" follows the alignment of its starting integer.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3071
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3072
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3073 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3074 All padding is filled with zeros by <a href="#pdf-string.pack"><code>string.pack</code></a>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3075 (and ignored by <a href="#pdf-string.unpack"><code>string.unpack</code></a>).
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3076
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3077
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3078
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3079
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3080
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3081
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3082
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3083 <h2>6.5 – <a name="6.5">UTF-8 Support</a></h2>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3084
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3085 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3086 This library provides basic support for UTF-8 encoding.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3087 It provides all its functions inside the table <a name="pdf-utf8"><code>utf8</code></a>.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3088 This library does not provide any support for Unicode other
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3089 than the handling of the encoding.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3090 Any operation that needs the meaning of a character,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3091 such as character classification, is outside its scope.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3092
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3093
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3094 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3095 Unless stated otherwise,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3096 all functions that expect a byte position as a parameter
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3097 assume that the given position is either the start of a byte sequence
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3098 or one plus the length of the subject string.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3099 As in the string library,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3100 negative indices count from the end of the string.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3101
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3102
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3103 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3104 <hr><h3><a name="pdf-utf8.char"><code>utf8.char (···)</code></a></h3>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3105 Receives zero or more integers,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3106 converts each one to its corresponding UTF-8 byte sequence
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3107 and returns a string with the concatenation of all these sequences.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3108
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3109
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3110
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3111
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3112 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3113 <hr><h3><a name="pdf-utf8.charpattern"><code>utf8.charpattern</code></a></h3>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3114 The pattern (a string, not a function) "<code>[\0-\x7F\xC2-\xF4][\x80-\xBF]*</code>"
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3115 (see <a href="#6.4.1">§6.4.1</a>),
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3116 which matches exactly one UTF-8 byte sequence,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3117 assuming that the subject is a valid UTF-8 string.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3118
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3119
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3120
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3121
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3122 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3123 <hr><h3><a name="pdf-utf8.codes"><code>utf8.codes (s)</code></a></h3>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3124
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3125
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3126 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3127 Returns values so that the construction
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3128
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3129 <pre>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3130 for p, c in utf8.codes(s) do <em>body</em> end
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3131 </pre><p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3132 will iterate over all characters in string <code>s</code>,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3133 with <code>p</code> being the position (in bytes) and <code>c</code> the code point
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3134 of each character.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3135 It raises an error if it meets any invalid byte sequence.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3136
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3137
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3138
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3139
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3140 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3141 <hr><h3><a name="pdf-utf8.codepoint"><code>utf8.codepoint (s [, i [, j]])</code></a></h3>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3142 Returns the codepoints (as integers) from all characters in <code>s</code>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3143 that start between byte position <code>i</code> and <code>j</code> (both included).
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3144 The default for <code>i</code> is 1 and for <code>j</code> is <code>i</code>.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3145 It raises an error if it meets any invalid byte sequence.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3146
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3147
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3148
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3149
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3150 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3151 <hr><h3><a name="pdf-utf8.len"><code>utf8.len (s [, i [, j]])</code></a></h3>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3152 Returns the number of UTF-8 characters in string <code>s</code>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3153 that start between positions <code>i</code> and <code>j</code> (both inclusive).
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3154 The default for <code>i</code> is 1 and for <code>j</code> is -1.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3155 If it finds any invalid byte sequence,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3156 returns a false value plus the position of the first invalid byte.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3157
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3158
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3159
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3160
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3161 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3162 <hr><h3><a name="pdf-utf8.offset"><code>utf8.offset (s, n [, i])</code></a></h3>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3163 Returns the position (in bytes) where the encoding of the
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3164 <code>n</code>-th character of <code>s</code>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3165 (counting from position <code>i</code>) starts.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3166 A negative <code>n</code> gets characters before position <code>i</code>.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3167 The default for <code>i</code> is 1 when <code>n</code> is non-negative
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3168 and <code>#s + 1</code> otherwise,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3169 so that <code>utf8.offset(s, -n)</code> gets the offset of the
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3170 <code>n</code>-th character from the end of the string.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3171 If the specified character is neither in the subject
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3172 nor right after its end,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3173 the function returns <b>nil</b>.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3174
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3175
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3176 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3177 As a special case,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3178 when <code>n</code> is 0 the function returns the start of the encoding
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3179 of the character that contains the <code>i</code>-th byte of <code>s</code>.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3180
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3181
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3182 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3183 This function assumes that <code>s</code> is a valid UTF-8 string.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3184
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3185
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3186
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3187
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3188
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3189
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3190
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3191 <h2>6.6 – <a name="6.6">Table Manipulation</a></h2>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3192
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3193 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3194 This library provides generic functions for table manipulation.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3195 It provides all its functions inside the table <a name="pdf-table"><code>table</code></a>.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3196
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3197
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3198 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3199 Remember that, whenever an operation needs the length of a table,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3200 the table must be a proper sequence
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3201 or have a <code>__len</code> metamethod (see <a href="#3.4.7">§3.4.7</a>).
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3202 All functions ignore non-numeric keys
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3203 in the tables given as arguments.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3204
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3205
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3206 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3207 <hr><h3><a name="pdf-table.concat"><code>table.concat (list [, sep [, i [, j]]])</code></a></h3>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3208
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3209
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3210 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3211 Given a list where all elements are strings or numbers,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3212 returns the string <code>list[i]..sep..list[i+1] ··· sep..list[j]</code>.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3213 The default value for <code>sep</code> is the empty string,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3214 the default for <code>i</code> is 1,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3215 and the default for <code>j</code> is <code>#list</code>.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3216 If <code>i</code> is greater than <code>j</code>, returns the empty string.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3217
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3218
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3219
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3220
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3221 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3222 <hr><h3><a name="pdf-table.insert"><code>table.insert (list, [pos,] value)</code></a></h3>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3223
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3224
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3225 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3226 Inserts element <code>value</code> at position <code>pos</code> in <code>list</code>,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3227 shifting up the elements
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3228 <code>list[pos], list[pos+1], ···, list[#list]</code>.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3229 The default value for <code>pos</code> is <code>#list+1</code>,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3230 so that a call <code>table.insert(t,x)</code> inserts <code>x</code> at the end
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3231 of list <code>t</code>.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3232
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3233
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3234
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3235
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3236 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3237 <hr><h3><a name="pdf-table.move"><code>table.move (a1, f, e, t [,a2])</code></a></h3>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3238
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3239
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3240 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3241 Moves elements from table <code>a1</code> to table <code>a2</code>.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3242 This function performs the equivalent to the following
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3243 multiple assignment:
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3244 <code>a2[t],··· = a1[f],···,a1[e]</code>.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3245 The default for <code>a2</code> is <code>a1</code>.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3246 The destination range can overlap with the source range.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3247 Index <code>f</code> must be positive.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3248
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3249
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3250
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3251
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3252 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3253 <hr><h3><a name="pdf-table.pack"><code>table.pack (···)</code></a></h3>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3254
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3255
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3256 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3257 Returns a new table with all parameters stored into keys 1, 2, etc.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3258 and with a field "<code>n</code>" with the total number of parameters.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3259 Note that the resulting table may not be a sequence.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3260
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3261
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3262
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3263
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3264 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3265 <hr><h3><a name="pdf-table.remove"><code>table.remove (list [, pos])</code></a></h3>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3266
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3267
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3268 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3269 Removes from <code>list</code> the element at position <code>pos</code>,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3270 returning the value of the removed element.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3271 When <code>pos</code> is an integer between 1 and <code>#list</code>,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3272 it shifts down the elements
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3273 <code>list[pos+1], list[pos+2], ···, list[#list]</code>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3274 and erases element <code>list[#list]</code>;
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3275 The index <code>pos</code> can also be 0 when <code>#list</code> is 0,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3276 or <code>#list + 1</code>;
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3277 in those cases, the function erases the element <code>list[pos]</code>.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3278
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3279
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3280 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3281 The default value for <code>pos</code> is <code>#list</code>,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3282 so that a call <code>table.remove(l)</code> removes the last element
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3283 of list <code>l</code>.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3284
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3285
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3286
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3287
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3288 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3289 <hr><h3><a name="pdf-table.sort"><code>table.sort (list [, comp])</code></a></h3>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3290
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3291
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3292 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3293 Sorts list elements in a given order, <em>in-place</em>,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3294 from <code>list[1]</code> to <code>list[#list]</code>.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3295 If <code>comp</code> is given,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3296 then it must be a function that receives two list elements
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3297 and returns true when the first element must come
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3298 before the second in the final order
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3299 (so that <code>not comp(list[i+1],list[i])</code> will be true after the sort).
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3300 If <code>comp</code> is not given,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3301 then the standard Lua operator <code><</code> is used instead.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3302
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3303
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3304 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3305 The sort algorithm is not stable;
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3306 that is, elements considered equal by the given order
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3307 may have their relative positions changed by the sort.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3308
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3309
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3310
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3311
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3312 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3313 <hr><h3><a name="pdf-table.unpack"><code>table.unpack (list [, i [, j]])</code></a></h3>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3314
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3315
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3316 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3317 Returns the elements from the given list.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3318 This function is equivalent to
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3319
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3320 <pre>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3321 return list[i], list[i+1], ···, list[j]
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3322 </pre><p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3323 By default, <code>i</code> is 1 and <code>j</code> is <code>#list</code>.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3324
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3325
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3326
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3327
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3328
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3329
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3330
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3331 <h2>6.7 – <a name="6.7">Mathematical Functions</a></h2>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3332
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3333 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3334 This library provides basic mathematical functions.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3335 It provides all its functions and constants inside the table <a name="pdf-math"><code>math</code></a>.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3336 Functions with the annotation "<code>integer/float</code>" give
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3337 integer results for integer arguments
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3338 and float results for float (or mixed) arguments.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3339 Rounding functions
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3340 (<a href="#pdf-math.ceil"><code>math.ceil</code></a>, <a href="#pdf-math.floor"><code>math.floor</code></a>, and <a href="#pdf-math.modf"><code>math.modf</code></a>)
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3341 return an integer when the result fits in the range of an integer,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3342 or a float otherwise.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3343
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3344
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3345 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3346 <hr><h3><a name="pdf-math.abs"><code>math.abs (x)</code></a></h3>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3347
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3348
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3349 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3350 Returns the absolute value of <code>x</code>. (integer/float)
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3351
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3352
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3353
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3354
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3355 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3356 <hr><h3><a name="pdf-math.acos"><code>math.acos (x)</code></a></h3>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3357
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3358
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3359 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3360 Returns the arc cosine of <code>x</code> (in radians).
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3361
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3362
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3363
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3364
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3365 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3366 <hr><h3><a name="pdf-math.asin"><code>math.asin (x)</code></a></h3>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3367
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3368
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3369 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3370 Returns the arc sine of <code>x</code> (in radians).
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3371
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3372
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3373
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3374
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3375 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3376 <hr><h3><a name="pdf-math.atan"><code>math.atan (y [, x])</code></a></h3>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3377
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3378
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3379 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3380
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3381 Returns the arc tangent of <code>y/x</code> (in radians),
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3382 but uses the signs of both parameters to find the
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3383 quadrant of the result.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3384 (It also handles correctly the case of <code>x</code> being zero.)
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3385
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3386
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3387 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3388 The default value for <code>x</code> is 1,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3389 so that the call <code>math.atan(y)</code>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3390 returns the arc tangent of <code>y</code>.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3391
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3392
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3393
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3394
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3395 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3396 <hr><h3><a name="pdf-math.ceil"><code>math.ceil (x)</code></a></h3>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3397
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3398
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3399 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3400 Returns the smallest integral value larger than or equal to <code>x</code>.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3401
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3402
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3403
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3404
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3405 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3406 <hr><h3><a name="pdf-math.cos"><code>math.cos (x)</code></a></h3>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3407
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3408
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3409 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3410 Returns the cosine of <code>x</code> (assumed to be in radians).
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3411
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3412
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3413
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3414
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3415 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3416 <hr><h3><a name="pdf-math.deg"><code>math.deg (x)</code></a></h3>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3417
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3418
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3419 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3420 Converts the angle <code>x</code> from radians to degrees.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3421
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3422
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3423
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3424
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3425 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3426 <hr><h3><a name="pdf-math.exp"><code>math.exp (x)</code></a></h3>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3427
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3428
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3429 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3430 Returns the value <em>e<sup>x</sup></em>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3431 (where <code>e</code> is the base of natural logarithms).
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3432
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3433
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3434
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3435
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3436 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3437 <hr><h3><a name="pdf-math.floor"><code>math.floor (x)</code></a></h3>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3438
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3439
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3440 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3441 Returns the largest integral value smaller than or equal to <code>x</code>.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3442
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3443
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3444
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3445
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3446 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3447 <hr><h3><a name="pdf-math.fmod"><code>math.fmod (x, y)</code></a></h3>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3448
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3449
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3450 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3451 Returns the remainder of the division of <code>x</code> by <code>y</code>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3452 that rounds the quotient towards zero. (integer/float)
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3453
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3454
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3455
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3456
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3457 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3458 <hr><h3><a name="pdf-math.huge"><code>math.huge</code></a></h3>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3459
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3460
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3461 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3462 The float value <code>HUGE_VAL</code>,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3463 a value larger than any other numerical value.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3464
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3465
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3466
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3467
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3468 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3469 <hr><h3><a name="pdf-math.log"><code>math.log (x [, base])</code></a></h3>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3470
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3471
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3472 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3473 Returns the logarithm of <code>x</code> in the given base.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3474 The default for <code>base</code> is <em>e</em>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3475 (so that the function returns the natural logarithm of <code>x</code>).
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3476
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3477
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3478
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3479
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3480 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3481 <hr><h3><a name="pdf-math.max"><code>math.max (x, ···)</code></a></h3>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3482
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3483
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3484 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3485 Returns the argument with the maximum value,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3486 according to the Lua operator <code><</code>. (integer/float)
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3487
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3488
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3489
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3490
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3491 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3492 <hr><h3><a name="pdf-math.maxinteger"><code>math.maxinteger</code></a></h3>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3493 An integer with the maximum value for an integer.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3494
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3495
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3496
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3497
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3498 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3499 <hr><h3><a name="pdf-math.min"><code>math.min (x, ···)</code></a></h3>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3500
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3501
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3502 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3503 Returns the argument with the minimum value,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3504 according to the Lua operator <code><</code>. (integer/float)
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3505
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3506
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3507
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3508
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3509 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3510 <hr><h3><a name="pdf-math.mininteger"><code>math.mininteger</code></a></h3>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3511 An integer with the minimum value for an integer.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3512
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3513
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3514
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3515
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3516 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3517 <hr><h3><a name="pdf-math.modf"><code>math.modf (x)</code></a></h3>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3518
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3519
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3520 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3521 Returns the integral part of <code>x</code> and the fractional part of <code>x</code>.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3522 Its second result is always a float.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3523
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3524
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3525
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3526
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3527 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3528 <hr><h3><a name="pdf-math.pi"><code>math.pi</code></a></h3>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3529
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3530
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3531 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3532 The value of <em>π</em>.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3533
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3534
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3535
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3536
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3537 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3538 <hr><h3><a name="pdf-math.rad"><code>math.rad (x)</code></a></h3>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3539
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3540
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3541 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3542 Converts the angle <code>x</code> from degrees to radians.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3543
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3544
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3545
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3546
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3547 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3548 <hr><h3><a name="pdf-math.random"><code>math.random ([m [, n]])</code></a></h3>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3549
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3550
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3551 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3552 When called without arguments,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3553 returns a pseudo-random float with uniform distribution
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3554 in the range <em>[0,1)</em>.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3555 When called with two integers <code>m</code> and <code>n</code>,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3556 <code>math.random</code> returns a pseudo-random integer
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3557 with uniform distribution in the range <em>[m, n]</em>.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3558 (The value <em>m-n</em> cannot be negative and must fit in a Lua integer.)
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3559 The call <code>math.random(n)</code> is equivalent to <code>math.random(1,n)</code>.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3560
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3561
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3562 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3563 This function is an interface to the underling
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3564 pseudo-random generator function provided by C.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3565 No guarantees can be given for its statistical properties.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3566
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3567
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3568
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3569
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3570 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3571 <hr><h3><a name="pdf-math.randomseed"><code>math.randomseed (x)</code></a></h3>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3572
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3573
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3574 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3575 Sets <code>x</code> as the "seed"
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3576 for the pseudo-random generator:
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3577 equal seeds produce equal sequences of numbers.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3578
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3579
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3580
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3581
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3582 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3583 <hr><h3><a name="pdf-math.sin"><code>math.sin (x)</code></a></h3>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3584
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3585
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3586 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3587 Returns the sine of <code>x</code> (assumed to be in radians).
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3588
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3589
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3590
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3591
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3592 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3593 <hr><h3><a name="pdf-math.sqrt"><code>math.sqrt (x)</code></a></h3>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3594
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3595
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3596 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3597 Returns the square root of <code>x</code>.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3598 (You can also use the expression <code>x^0.5</code> to compute this value.)
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3599
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3600
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3601
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3602
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3603 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3604 <hr><h3><a name="pdf-math.tan"><code>math.tan (x)</code></a></h3>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3605
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3606
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3607 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3608 Returns the tangent of <code>x</code> (assumed to be in radians).
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3609
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3610
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3611
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3612
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3613 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3614 <hr><h3><a name="pdf-math.tointeger"><code>math.tointeger (x)</code></a></h3>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3615
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3616
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3617 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3618 If the value <code>x</code> is convertible to an integer,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3619 returns that integer.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3620 Otherwise, returns <b>nil</b>.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3621
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3622
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3623
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3624
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3625 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3626 <hr><h3><a name="pdf-math.type"><code>math.type (x)</code></a></h3>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3627
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3628
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3629 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3630 Returns "<code>integer</code>" if <code>x</code> is an integer,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3631 "<code>float</code>" if it is a float,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3632 or <b>nil</b> if <code>x</code> is not a number.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3633
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3634
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3635
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3636
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3637 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3638 <hr><h3><a name="pdf-math.ult"><code>math.ult (m, n)</code></a></h3>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3639
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3640
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3641 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3642 Returns a boolean,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3643 true if integer <code>m</code> is below integer <code>n</code> when
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3644 they are compared as unsigned integers.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3645
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3646
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3647
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3648
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3649
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3650
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3651
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3652 <h2>6.8 – <a name="6.8">Input and Output Facilities</a></h2>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3653
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3654 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3655 The I/O library provides two different styles for file manipulation.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3656 The first one uses implicit file handles;
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3657 that is, there are operations to set a default input file and a
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3658 default output file,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3659 and all input/output operations are over these default files.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3660 The second style uses explicit file handles.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3661
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3662
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3663 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3664 When using implicit file handles,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3665 all operations are supplied by table <a name="pdf-io"><code>io</code></a>.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3666 When using explicit file handles,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3667 the operation <a href="#pdf-io.open"><code>io.open</code></a> returns a file handle
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3668 and then all operations are supplied as methods of the file handle.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3669
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3670
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3671 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3672 The table <code>io</code> also provides
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3673 three predefined file handles with their usual meanings from C:
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3674 <a name="pdf-io.stdin"><code>io.stdin</code></a>, <a name="pdf-io.stdout"><code>io.stdout</code></a>, and <a name="pdf-io.stderr"><code>io.stderr</code></a>.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3675 The I/O library never closes these files.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3676
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3677
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3678 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3679 Unless otherwise stated,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3680 all I/O functions return <b>nil</b> on failure
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3681 (plus an error message as a second result and
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3682 a system-dependent error code as a third result)
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3683 and some value different from <b>nil</b> on success.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3684 On non-POSIX systems,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3685 the computation of the error message and error code
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3686 in case of errors
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3687 may be not thread safe,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3688 because they rely on the global C variable <code>errno</code>.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3689
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3690
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3691 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3692 <hr><h3><a name="pdf-io.close"><code>io.close ([file])</code></a></h3>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3693
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3694
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3695 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3696 Equivalent to <code>file:close()</code>.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3697 Without a <code>file</code>, closes the default output file.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3698
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3699
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3700
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3701
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3702 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3703 <hr><h3><a name="pdf-io.flush"><code>io.flush ()</code></a></h3>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3704
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3705
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3706 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3707 Equivalent to <code>io.output():flush()</code>.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3708
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3709
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3710
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3711
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3712 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3713 <hr><h3><a name="pdf-io.input"><code>io.input ([file])</code></a></h3>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3714
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3715
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3716 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3717 When called with a file name, it opens the named file (in text mode),
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3718 and sets its handle as the default input file.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3719 When called with a file handle,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3720 it simply sets this file handle as the default input file.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3721 When called without parameters,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3722 it returns the current default input file.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3723
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3724
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3725 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3726 In case of errors this function raises the error,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3727 instead of returning an error code.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3728
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3729
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3730
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3731
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3732 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3733 <hr><h3><a name="pdf-io.lines"><code>io.lines ([filename ···])</code></a></h3>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3734
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3735
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3736 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3737 Opens the given file name in read mode
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3738 and returns an iterator function that
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3739 works like <code>file:lines(···)</code> over the opened file.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3740 When the iterator function detects the end of file,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3741 it returns no values (to finish the loop) and automatically closes the file.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3742
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3743
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3744 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3745 The call <code>io.lines()</code> (with no file name) is equivalent
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3746 to <code>io.input():lines("*l")</code>;
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3747 that is, it iterates over the lines of the default input file.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3748 In this case it does not close the file when the loop ends.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3749
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3750
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3751 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3752 In case of errors this function raises the error,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3753 instead of returning an error code.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3754
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3755
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3756
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3757
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3758 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3759 <hr><h3><a name="pdf-io.open"><code>io.open (filename [, mode])</code></a></h3>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3760
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3761
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3762 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3763 This function opens a file,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3764 in the mode specified in the string <code>mode</code>.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3765 It returns a new file handle,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3766 or, in case of errors, <b>nil</b> plus an error message.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3767
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3768
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3769 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3770 The <code>mode</code> string can be any of the following:
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3771
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3772 <ul>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3773 <li><b>"<code>r</code>": </b> read mode (the default);</li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3774 <li><b>"<code>w</code>": </b> write mode;</li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3775 <li><b>"<code>a</code>": </b> append mode;</li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3776 <li><b>"<code>r+</code>": </b> update mode, all previous data is preserved;</li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3777 <li><b>"<code>w+</code>": </b> update mode, all previous data is erased;</li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3778 <li><b>"<code>a+</code>": </b> append update mode, previous data is preserved,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3779 writing is only allowed at the end of file.</li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3780 </ul><p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3781 The <code>mode</code> string can also have a '<code>b</code>' at the end,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3782 which is needed in some systems to open the file in binary mode.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3783
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3784
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3785
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3786
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3787 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3788 <hr><h3><a name="pdf-io.output"><code>io.output ([file])</code></a></h3>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3789
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3790
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3791 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3792 Similar to <a href="#pdf-io.input"><code>io.input</code></a>, but operates over the default output file.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3793
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3794
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3795
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3796
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3797 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3798 <hr><h3><a name="pdf-io.popen"><code>io.popen (prog [, mode])</code></a></h3>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3799
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3800
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3801 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3802 This function is system dependent and is not available
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3803 on all platforms.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3804
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3805
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3806 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3807 Starts program <code>prog</code> in a separated process and returns
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3808 a file handle that you can use to read data from this program
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3809 (if <code>mode</code> is <code>"r"</code>, the default)
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3810 or to write data to this program
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3811 (if <code>mode</code> is <code>"w"</code>).
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3812
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3813
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3814
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3815
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3816 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3817 <hr><h3><a name="pdf-io.read"><code>io.read (···)</code></a></h3>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3818
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3819
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3820 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3821 Equivalent to <code>io.input():read(···)</code>.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3822
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3823
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3824
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3825
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3826 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3827 <hr><h3><a name="pdf-io.tmpfile"><code>io.tmpfile ()</code></a></h3>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3828
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3829
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3830 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3831 Returns a handle for a temporary file.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3832 This file is opened in update mode
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3833 and it is automatically removed when the program ends.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3834
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3835
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3836
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3837
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3838 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3839 <hr><h3><a name="pdf-io.type"><code>io.type (obj)</code></a></h3>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3840
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3841
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3842 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3843 Checks whether <code>obj</code> is a valid file handle.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3844 Returns the string <code>"file"</code> if <code>obj</code> is an open file handle,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3845 <code>"closed file"</code> if <code>obj</code> is a closed file handle,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3846 or <b>nil</b> if <code>obj</code> is not a file handle.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3847
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3848
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3849
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3850
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3851 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3852 <hr><h3><a name="pdf-io.write"><code>io.write (···)</code></a></h3>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3853
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3854
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3855 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3856 Equivalent to <code>io.output():write(···)</code>.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3857
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3858
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3859
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3860
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3861 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3862 <hr><h3><a name="pdf-file:close"><code>file:close ()</code></a></h3>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3863
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3864
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3865 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3866 Closes <code>file</code>.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3867 Note that files are automatically closed when
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3868 their handles are garbage collected,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3869 but that takes an unpredictable amount of time to happen.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3870
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3871
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3872 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3873 When closing a file handle created with <a href="#pdf-io.popen"><code>io.popen</code></a>,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3874 <a href="#pdf-file:close"><code>file:close</code></a> returns the same values
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3875 returned by <a href="#pdf-os.execute"><code>os.execute</code></a>.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3876
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3877
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3878
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3879
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3880 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3881 <hr><h3><a name="pdf-file:flush"><code>file:flush ()</code></a></h3>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3882
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3883
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3884 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3885 Saves any written data to <code>file</code>.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3886
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3887
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3888
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3889
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3890 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3891 <hr><h3><a name="pdf-file:lines"><code>file:lines (···)</code></a></h3>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3892
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3893
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3894 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3895 Returns an iterator function that,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3896 each time it is called,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3897 reads the file according to the given formats.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3898 When no format is given,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3899 uses "<code>l</code>" as a default.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3900 As an example, the construction
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3901
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3902 <pre>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3903 for c in file:lines(1) do <em>body</em> end
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3904 </pre><p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3905 will iterate over all characters of the file,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3906 starting at the current position.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3907 Unlike <a href="#pdf-io.lines"><code>io.lines</code></a>, this function does not close the file
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3908 when the loop ends.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3909
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3910
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3911 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3912 In case of errors this function raises the error,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3913 instead of returning an error code.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3914
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3915
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3916
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3917
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3918 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3919 <hr><h3><a name="pdf-file:read"><code>file:read (···)</code></a></h3>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3920
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3921
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3922 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3923 Reads the file <code>file</code>,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3924 according to the given formats, which specify what to read.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3925 For each format,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3926 the function returns a string or a number with the characters read,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3927 or <b>nil</b> if it cannot read data with the specified format.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3928 (In this latter case,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3929 the function does not read subsequent formats.)
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3930 When called without formats,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3931 it uses a default format that reads the next line
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3932 (see below).
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3933
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3934
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3935 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3936 The available formats are
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3937
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3938 <ul>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3939
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3940 <li><b>"<code>n</code>": </b>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3941 reads a numeral and returns it as a float or an integer,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3942 following the lexical conventions of Lua.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3943 (The numeral may have leading spaces and a sign.)
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3944 This format always reads the longest input sequence that
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3945 is a valid prefix for a number;
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3946 if that prefix does not form a valid number
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3947 (e.g., an empty string, "<code>0x</code>", or "<code>3.4e-</code>"),
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3948 it is discarded and the function returns <b>nil</b>.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3949 </li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3950
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3951 <li><b>"<code>i</code>": </b>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3952 reads an integral number and returns it as an integer.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3953 </li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3954
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3955 <li><b>"<code>a</code>": </b>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3956 reads the whole file, starting at the current position.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3957 On end of file, it returns the empty string.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3958 </li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3959
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3960 <li><b>"<code>l</code>": </b>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3961 reads the next line skipping the end of line,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3962 returning <b>nil</b> on end of file.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3963 This is the default format.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3964 </li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3965
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3966 <li><b>"<code>L</code>": </b>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3967 reads the next line keeping the end-of-line character (if present),
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3968 returning <b>nil</b> on end of file.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3969 </li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3970
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3971 <li><b><em>number</em>: </b>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3972 reads a string with up to this number of bytes,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3973 returning <b>nil</b> on end of file.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3974 If <code>number</code> is zero,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3975 it reads nothing and returns an empty string,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3976 or <b>nil</b> on end of file.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3977 </li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3978
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3979 </ul><p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3980 The formats "<code>l</code>" and "<code>L</code>" should be used only for text files.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3981
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3982
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3983
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3984
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3985 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3986 <hr><h3><a name="pdf-file:seek"><code>file:seek ([whence [, offset]])</code></a></h3>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3987
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3988
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3989 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3990 Sets and gets the file position,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3991 measured from the beginning of the file,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3992 to the position given by <code>offset</code> plus a base
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3993 specified by the string <code>whence</code>, as follows:
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3994
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3995 <ul>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3996 <li><b>"<code>set</code>": </b> base is position 0 (beginning of the file);</li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3997 <li><b>"<code>cur</code>": </b> base is current position;</li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3998 <li><b>"<code>end</code>": </b> base is end of file;</li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	3999 </ul><p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4000 In case of success, <code>seek</code> returns the final file position,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4001 measured in bytes from the beginning of the file.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4002 If <code>seek</code> fails, it returns <b>nil</b>,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4003 plus a string describing the error.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4004
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4005
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4006 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4007 The default value for <code>whence</code> is <code>"cur"</code>,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4008 and for <code>offset</code> is 0.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4009 Therefore, the call <code>file:seek()</code> returns the current
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4010 file position, without changing it;
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4011 the call <code>file:seek("set")</code> sets the position to the
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4012 beginning of the file (and returns 0);
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4013 and the call <code>file:seek("end")</code> sets the position to the
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4014 end of the file, and returns its size.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4015
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4016
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4017
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4018
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4019 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4020 <hr><h3><a name="pdf-file:setvbuf"><code>file:setvbuf (mode [, size])</code></a></h3>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4021
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4022
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4023 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4024 Sets the buffering mode for an output file.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4025 There are three available modes:
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4026
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4027 <ul>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4028
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4029 <li><b>"<code>no</code>": </b>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4030 no buffering; the result of any output operation appears immediately.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4031 </li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4032
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4033 <li><b>"<code>full</code>": </b>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4034 full buffering; output operation is performed only
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4035 when the buffer is full or when
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4036 you explicitly <code>flush</code> the file (see <a href="#pdf-io.flush"><code>io.flush</code></a>).
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4037 </li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4038
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4039 <li><b>"<code>line</code>": </b>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4040 line buffering; output is buffered until a newline is output
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4041 or there is any input from some special files
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4042 (such as a terminal device).
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4043 </li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4044
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4045 </ul><p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4046 For the last two cases, <code>size</code>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4047 specifies the size of the buffer, in bytes.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4048 The default is an appropriate size.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4049
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4050
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4051
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4052
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4053 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4054 <hr><h3><a name="pdf-file:write"><code>file:write (···)</code></a></h3>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4055
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4056
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4057 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4058 Writes the value of each of its arguments to <code>file</code>.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4059 The arguments must be strings or numbers.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4060
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4061
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4062 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4063 In case of success, this function returns <code>file</code>.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4064 Otherwise it returns <b>nil</b> plus a string describing the error.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4065
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4066
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4067
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4068
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4069
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4070
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4071
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4072 <h2>6.9 – <a name="6.9">Operating System Facilities</a></h2>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4073
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4074 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4075 This library is implemented through table <a name="pdf-os"><code>os</code></a>.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4076
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4077
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4078 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4079 <hr><h3><a name="pdf-os.clock"><code>os.clock ()</code></a></h3>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4080
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4081
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4082 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4083 Returns an approximation of the amount in seconds of CPU time
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4084 used by the program.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4085
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4086
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4087
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4088
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4089 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4090 <hr><h3><a name="pdf-os.date"><code>os.date ([format [, time]])</code></a></h3>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4091
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4092
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4093 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4094 Returns a string or a table containing date and time,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4095 formatted according to the given string <code>format</code>.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4096
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4097
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4098 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4099 If the <code>time</code> argument is present,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4100 this is the time to be formatted
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4101 (see the <a href="#pdf-os.time"><code>os.time</code></a> function for a description of this value).
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4102 Otherwise, <code>date</code> formats the current time.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4103
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4104
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4105 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4106 If <code>format</code> starts with '<code>!</code>',
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4107 then the date is formatted in Coordinated Universal Time.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4108 After this optional character,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4109 if <code>format</code> is the string "<code>*t</code>",
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4110 then <code>date</code> returns a table with the following fields:
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4111 <code>year</code> (four digits), <code>month</code> (1–12), <code>day</code> (1–31),
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4112 <code>hour</code> (0–23), <code>min</code> (0–59), <code>sec</code> (0–61),
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4113 <code>wday</code> (weekday, Sunday is 1),
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4114 <code>yday</code> (day of the year),
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4115 and <code>isdst</code> (daylight saving flag, a boolean).
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4116 This last field may be absent
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4117 if the information is not available.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4118
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4119
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4120 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4121 If <code>format</code> is not "<code>*t</code>",
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4122 then <code>date</code> returns the date as a string,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4123 formatted according to the same rules as the ISO C function <code>strftime</code>.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4124
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4125
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4126 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4127 When called without arguments,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4128 <code>date</code> returns a reasonable date and time representation that depends on
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4129 the host system and on the current locale
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4130 (that is, <code>os.date()</code> is equivalent to <code>os.date("%c")</code>).
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4131
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4132
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4133 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4134 On non-POSIX systems,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4135 this function may be not thread safe
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4136 because of its reliance on C function <code>gmtime</code> and C function <code>localtime</code>.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4137
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4138
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4139
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4140
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4141 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4142 <hr><h3><a name="pdf-os.difftime"><code>os.difftime (t2, t1)</code></a></h3>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4143
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4144
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4145 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4146 Returns the difference, in seconds,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4147 from time <code>t1</code> to time <code>t2</code>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4148 (where the times are values returned by <a href="#pdf-os.time"><code>os.time</code></a>).
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4149 In POSIX, Windows, and some other systems,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4150 this value is exactly <code>t2</code><em>-</em><code>t1</code>.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4151
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4152
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4153
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4154
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4155 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4156 <hr><h3><a name="pdf-os.execute"><code>os.execute ([command])</code></a></h3>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4157
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4158
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4159 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4160 This function is equivalent to the ISO C function <code>system</code>.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4161 It passes <code>command</code> to be executed by an operating system shell.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4162 Its first result is <b>true</b>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4163 if the command terminated successfully,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4164 or <b>nil</b> otherwise.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4165 After this first result
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4166 the function returns a string plus a number,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4167 as follows:
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4168
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4169 <ul>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4170
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4171 <li><b>"<code>exit</code>": </b>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4172 the command terminated normally;
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4173 the following number is the exit status of the command.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4174 </li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4175
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4176 <li><b>"<code>signal</code>": </b>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4177 the command was terminated by a signal;
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4178 the following number is the signal that terminated the command.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4179 </li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4180
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4181 </ul>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4182
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4183 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4184 When called without a <code>command</code>,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4185 <code>os.execute</code> returns a boolean that is true if a shell is available.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4186
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4187
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4188
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4189
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4190 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4191 <hr><h3><a name="pdf-os.exit"><code>os.exit ([code [, close]])</code></a></h3>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4192
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4193
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4194 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4195 Calls the ISO C function <code>exit</code> to terminate the host program.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4196 If <code>code</code> is <b>true</b>,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4197 the returned status is <code>EXIT_SUCCESS</code>;
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4198 if <code>code</code> is <b>false</b>,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4199 the returned status is <code>EXIT_FAILURE</code>;
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4200 if <code>code</code> is a number,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4201 the returned status is this number.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4202 The default value for <code>code</code> is <b>true</b>.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4203
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4204
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4205 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4206 If the optional second argument <code>close</code> is true,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4207 closes the Lua state before exiting.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4208
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4209
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4210
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4211
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4212 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4213 <hr><h3><a name="pdf-os.getenv"><code>os.getenv (varname)</code></a></h3>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4214
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4215
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4216 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4217 Returns the value of the process environment variable <code>varname</code>,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4218 or <b>nil</b> if the variable is not defined.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4219
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4220
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4221
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4222
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4223 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4224 <hr><h3><a name="pdf-os.remove"><code>os.remove (filename)</code></a></h3>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4225
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4226
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4227 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4228 Deletes the file (or empty directory, on POSIX systems)
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4229 with the given name.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4230 If this function fails, it returns <b>nil</b>,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4231 plus a string describing the error and the error code.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4232
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4233
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4234
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4235
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4236 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4237 <hr><h3><a name="pdf-os.rename"><code>os.rename (oldname, newname)</code></a></h3>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4238
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4239
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4240 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4241 Renames file or directory named <code>oldname</code> to <code>newname</code>.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4242 If this function fails, it returns <b>nil</b>,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4243 plus a string describing the error and the error code.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4244
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4245
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4246
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4247
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4248 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4249 <hr><h3><a name="pdf-os.setlocale"><code>os.setlocale (locale [, category])</code></a></h3>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4250
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4251
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4252 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4253 Sets the current locale of the program.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4254 <code>locale</code> is a system-dependent string specifying a locale;
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4255 <code>category</code> is an optional string describing which category to change:
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4256 <code>"all"</code>, <code>"collate"</code>, <code>"ctype"</code>,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4257 <code>"monetary"</code>, <code>"numeric"</code>, or <code>"time"</code>;
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4258 the default category is <code>"all"</code>.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4259 The function returns the name of the new locale,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4260 or <b>nil</b> if the request cannot be honored.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4261
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4262
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4263 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4264 If <code>locale</code> is the empty string,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4265 the current locale is set to an implementation-defined native locale.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4266 If <code>locale</code> is the string "<code>C</code>",
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4267 the current locale is set to the standard C locale.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4268
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4269
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4270 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4271 When called with <b>nil</b> as the first argument,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4272 this function only returns the name of the current locale
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4273 for the given category.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4274
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4275
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4276 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4277 This function may be not thread safe
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4278 because of its reliance on C function <code>setlocale</code>.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4279
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4280
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4281
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4282
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4283 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4284 <hr><h3><a name="pdf-os.time"><code>os.time ([table])</code></a></h3>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4285
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4286
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4287 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4288 Returns the current time when called without arguments,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4289 or a time representing the date and time specified by the given table.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4290 This table must have fields <code>year</code>, <code>month</code>, and <code>day</code>,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4291 and may have fields
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4292 <code>hour</code> (default is 12),
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4293 <code>min</code> (default is 0),
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4294 <code>sec</code> (default is 0),
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4295 and <code>isdst</code> (default is <b>nil</b>).
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4296 For a description of these fields, see the <a href="#pdf-os.date"><code>os.date</code></a> function.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4297
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4298
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4299 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4300 The returned value is a number, whose meaning depends on your system.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4301 In POSIX, Windows, and some other systems,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4302 this number counts the number
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4303 of seconds since some given start time (the "epoch").
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4304 In other systems, the meaning is not specified,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4305 and the number returned by <code>time</code> can be used only as an argument to
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4306 <a href="#pdf-os.date"><code>os.date</code></a> and <a href="#pdf-os.difftime"><code>os.difftime</code></a>.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4307
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4308
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4309
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4310
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4311 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4312 <hr><h3><a name="pdf-os.tmpname"><code>os.tmpname ()</code></a></h3>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4313
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4314
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4315 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4316 Returns a string with a file name that can
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4317 be used for a temporary file.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4318 The file must be explicitly opened before its use
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4319 and explicitly removed when no longer needed.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4320
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4321
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4322 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4323 On POSIX systems,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4324 this function also creates a file with that name,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4325 to avoid security risks.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4326 (Someone else might create the file with wrong permissions
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4327 in the time between getting the name and creating the file.)
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4328 You still have to open the file to use it
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4329 and to remove it (even if you do not use it).
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4330
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4331
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4332 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4333 When possible,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4334 you may prefer to use <a href="#pdf-io.tmpfile"><code>io.tmpfile</code></a>,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4335 which automatically removes the file when the program ends.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4336
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4337
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4338
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4339
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4340
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4341
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4342
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4343 <h2>6.10 – <a name="6.10">The Debug Library</a></h2>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4344
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4345 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4346 This library provides
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4347 the functionality of the debug interface (<a href="#4.9">§4.9</a>) to Lua programs.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4348 You should exert care when using this library.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4349 Several of its functions
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4350 violate basic assumptions about Lua code
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4351 (e.g., that variables local to a function
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4352 cannot be accessed from outside;
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4353 that userdata metatables cannot be changed by Lua code;
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4354 that Lua programs do not crash)
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4355 and therefore can compromise otherwise secure code.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4356 Moreover, some functions in this library may be slow.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4357
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4358
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4359 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4360 All functions in this library are provided
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4361 inside the <a name="pdf-debug"><code>debug</code></a> table.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4362 All functions that operate over a thread
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4363 have an optional first argument which is the
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4364 thread to operate over.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4365 The default is always the current thread.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4366
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4367
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4368 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4369 <hr><h3><a name="pdf-debug.debug"><code>debug.debug ()</code></a></h3>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4370
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4371
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4372 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4373 Enters an interactive mode with the user,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4374 running each string that the user enters.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4375 Using simple commands and other debug facilities,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4376 the user can inspect global and local variables,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4377 change their values, evaluate expressions, and so on.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4378 A line containing only the word <code>cont</code> finishes this function,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4379 so that the caller continues its execution.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4380
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4381
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4382 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4383 Note that commands for <code>debug.debug</code> are not lexically nested
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4384 within any function and so have no direct access to local variables.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4385
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4386
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4387
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4388
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4389 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4390 <hr><h3><a name="pdf-debug.gethook"><code>debug.gethook ([thread])</code></a></h3>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4391
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4392
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4393 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4394 Returns the current hook settings of the thread, as three values:
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4395 the current hook function, the current hook mask,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4396 and the current hook count
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4397 (as set by the <a href="#pdf-debug.sethook"><code>debug.sethook</code></a> function).
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4398
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4399
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4400
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4401
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4402 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4403 <hr><h3><a name="pdf-debug.getinfo"><code>debug.getinfo ([thread,] f [, what])</code></a></h3>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4404
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4405
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4406 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4407 Returns a table with information about a function.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4408 You can give the function directly
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4409 or you can give a number as the value of <code>f</code>,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4410 which means the function running at level <code>f</code> of the call stack
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4411 of the given thread:
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4412 level 0 is the current function (<code>getinfo</code> itself);
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4413 level 1 is the function that called <code>getinfo</code>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4414 (except for tail calls, which do not count on the stack);
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4415 and so on.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4416 If <code>f</code> is a number larger than the number of active functions,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4417 then <code>getinfo</code> returns <b>nil</b>.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4418
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4419
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4420 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4421 The returned table can contain all the fields returned by <a href="#lua_getinfo"><code>lua_getinfo</code></a>,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4422 with the string <code>what</code> describing which fields to fill in.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4423 The default for <code>what</code> is to get all information available,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4424 except the table of valid lines.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4425 If present,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4426 the option '<code>f</code>'
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4427 adds a field named <code>func</code> with the function itself.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4428 If present,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4429 the option '<code>L</code>'
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4430 adds a field named <code>activelines</code> with the table of
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4431 valid lines.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4432
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4433
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4434 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4435 For instance, the expression <code>debug.getinfo(1,"n").name</code> returns
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4436 a table with a name for the current function,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4437 if a reasonable name can be found,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4438 and the expression <code>debug.getinfo(print)</code>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4439 returns a table with all available information
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4440 about the <a href="#pdf-print"><code>print</code></a> function.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4441
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4442
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4443
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4444
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4445 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4446 <hr><h3><a name="pdf-debug.getlocal"><code>debug.getlocal ([thread,] f, local)</code></a></h3>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4447
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4448
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4449 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4450 This function returns the name and the value of the local variable
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4451 with index <code>local</code> of the function at level <code>f</code> of the stack.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4452 This function accesses not only explicit local variables,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4453 but also parameters, temporaries, etc.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4454
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4455
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4456 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4457 The first parameter or local variable has index 1, and so on,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4458 following the order that they are declared in the code,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4459 counting only the variables that are active
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4460 in the current scope of the function.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4461 Negative indices refer to vararg parameters;
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4462 -1 is the first vararg parameter.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4463 The function returns <b>nil</b> if there is no variable with the given index,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4464 and raises an error when called with a level out of range.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4465 (You can call <a href="#pdf-debug.getinfo"><code>debug.getinfo</code></a> to check whether the level is valid.)
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4466
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4467
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4468 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4469 Variable names starting with '<code>(</code>' (open parenthesis)
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4470 represent variables with no known names
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4471 (internal variables such as loop control variables,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4472 and variables from chunks saved without debug information).
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4473
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4474
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4475 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4476 The parameter <code>f</code> may also be a function.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4477 In that case, <code>getlocal</code> returns only the name of function parameters.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4478
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4479
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4480
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4481
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4482 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4483 <hr><h3><a name="pdf-debug.getmetatable"><code>debug.getmetatable (value)</code></a></h3>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4484
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4485
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4486 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4487 Returns the metatable of the given <code>value</code>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4488 or <b>nil</b> if it does not have a metatable.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4489
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4490
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4491
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4492
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4493 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4494 <hr><h3><a name="pdf-debug.getregistry"><code>debug.getregistry ()</code></a></h3>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4495
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4496
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4497 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4498 Returns the registry table (see <a href="#4.5">§4.5</a>).
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4499
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4500
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4501
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4502
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4503 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4504 <hr><h3><a name="pdf-debug.getupvalue"><code>debug.getupvalue (f, up)</code></a></h3>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4505
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4506
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4507 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4508 This function returns the name and the value of the upvalue
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4509 with index <code>up</code> of the function <code>f</code>.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4510 The function returns <b>nil</b> if there is no upvalue with the given index.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4511
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4512
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4513 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4514 Variable names starting with '<code>(</code>' (open parenthesis)
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4515 represent variables with no known names
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4516 (variables from chunks saved without debug information).
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4517
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4518
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4519
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4520
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4521 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4522 <hr><h3><a name="pdf-debug.getuservalue"><code>debug.getuservalue (u)</code></a></h3>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4523
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4524
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4525 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4526 Returns the Lua value associated to <code>u</code>.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4527 If <code>u</code> is not a userdata,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4528 returns <b>nil</b>.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4529
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4530
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4531
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4532
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4533 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4534 <hr><h3><a name="pdf-debug.sethook"><code>debug.sethook ([thread,] hook, mask [, count])</code></a></h3>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4535
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4536
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4537 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4538 Sets the given function as a hook.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4539 The string <code>mask</code> and the number <code>count</code> describe
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4540 when the hook will be called.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4541 The string mask may have any combination of the following characters,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4542 with the given meaning:
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4543
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4544 <ul>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4545 <li><b>'<code>c</code>': </b> the hook is called every time Lua calls a function;</li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4546 <li><b>'<code>r</code>': </b> the hook is called every time Lua returns from a function;</li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4547 <li><b>'<code>l</code>': </b> the hook is called every time Lua enters a new line of code.</li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4548 </ul><p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4549 Moreover,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4550 with a <code>count</code> different from zero,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4551 the hook is called also after every <code>count</code> instructions.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4552
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4553
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4554 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4555 When called without arguments,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4556 <a href="#pdf-debug.sethook"><code>debug.sethook</code></a> turns off the hook.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4557
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4558
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4559 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4560 When the hook is called, its first parameter is a string
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4561 describing the event that has triggered its call:
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4562 <code>"call"</code> (or <code>"tail call"</code>),
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4563 <code>"return"</code>,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4564 <code>"line"</code>, and <code>"count"</code>.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4565 For line events,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4566 the hook also gets the new line number as its second parameter.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4567 Inside a hook,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4568 you can call <code>getinfo</code> with level 2 to get more information about
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4569 the running function
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4570 (level 0 is the <code>getinfo</code> function,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4571 and level 1 is the hook function).
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4572
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4573
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4574
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4575
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4576 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4577 <hr><h3><a name="pdf-debug.setlocal"><code>debug.setlocal ([thread,] level, local, value)</code></a></h3>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4578
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4579
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4580 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4581 This function assigns the value <code>value</code> to the local variable
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4582 with index <code>local</code> of the function at level <code>level</code> of the stack.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4583 The function returns <b>nil</b> if there is no local
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4584 variable with the given index,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4585 and raises an error when called with a <code>level</code> out of range.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4586 (You can call <code>getinfo</code> to check whether the level is valid.)
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4587 Otherwise, it returns the name of the local variable.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4588
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4589
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4590 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4591 See <a href="#pdf-debug.getlocal"><code>debug.getlocal</code></a> for more information about
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4592 variable indices and names.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4593
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4594
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4595
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4596
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4597 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4598 <hr><h3><a name="pdf-debug.setmetatable"><code>debug.setmetatable (value, table)</code></a></h3>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4599
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4600
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4601 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4602 Sets the metatable for the given <code>value</code> to the given <code>table</code>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4603 (which can be <b>nil</b>).
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4604 Returns <code>value</code>.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4605
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4606
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4607
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4608
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4609 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4610 <hr><h3><a name="pdf-debug.setupvalue"><code>debug.setupvalue (f, up, value)</code></a></h3>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4611
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4612
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4613 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4614 This function assigns the value <code>value</code> to the upvalue
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4615 with index <code>up</code> of the function <code>f</code>.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4616 The function returns <b>nil</b> if there is no upvalue
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4617 with the given index.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4618 Otherwise, it returns the name of the upvalue.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4619
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4620
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4621
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4622
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4623 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4624 <hr><h3><a name="pdf-debug.setuservalue"><code>debug.setuservalue (udata, value)</code></a></h3>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4625
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4626
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4627 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4628 Sets the given <code>value</code> as
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4629 the Lua value associated to the given <code>udata</code>.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4630 <code>udata</code> must be a full userdata.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4631
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4632
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4633 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4634 Returns <code>udata</code>.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4635
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4636
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4637
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4638
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4639 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4640 <hr><h3><a name="pdf-debug.traceback"><code>debug.traceback ([thread,] [message [, level]])</code></a></h3>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4641
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4642
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4643 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4644 If <code>message</code> is present but is neither a string nor <b>nil</b>,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4645 this function returns <code>message</code> without further processing.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4646 Otherwise,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4647 it returns a string with a traceback of the call stack.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4648 The optional <code>message</code> string is appended
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4649 at the beginning of the traceback.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4650 An optional <code>level</code> number tells at which level
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4651 to start the traceback
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4652 (default is 1, the function calling <code>traceback</code>).
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4653
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4654
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4655
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4656
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4657 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4658 <hr><h3><a name="pdf-debug.upvalueid"><code>debug.upvalueid (f, n)</code></a></h3>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4659
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4660
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4661 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4662 Returns a unique identifier (as a light userdata)
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4663 for the upvalue numbered <code>n</code>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4664 from the given function.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4665
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4666
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4667 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4668 These unique identifiers allow a program to check whether different
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4669 closures share upvalues.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4670 Lua closures that share an upvalue
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4671 (that is, that access a same external local variable)
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4672 will return identical ids for those upvalue indices.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4673
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4674
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4675
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4676
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4677 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4678 <hr><h3><a name="pdf-debug.upvaluejoin"><code>debug.upvaluejoin (f1, n1, f2, n2)</code></a></h3>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4679
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4680
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4681 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4682 Make the <code>n1</code>-th upvalue of the Lua closure <code>f1</code>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4683 refer to the <code>n2</code>-th upvalue of the Lua closure <code>f2</code>.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4684
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4685
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4686
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4687
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4688
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4689
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4690
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4691 <h1>7 – <a name="7">Lua Standalone</a></h1>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4692
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4693 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4694 Although Lua has been designed as an extension language,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4695 to be embedded in a host C program,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4696 it is also frequently used as a standalone language.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4697 An interpreter for Lua as a standalone language,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4698 called simply <code>lua</code>,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4699 is provided with the standard distribution.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4700 The standalone interpreter includes
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4701 all standard libraries, including the debug library.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4702 Its usage is:
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4703
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4704 <pre>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4705 lua [options] [script [args]]
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4706 </pre><p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4707 The options are:
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4708
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4709 <ul>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4710 <li><b><code>-e <em>stat</em></code>: </b> executes string <em>stat</em>;</li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4711 <li><b><code>-l <em>mod</em></code>: </b> "requires" <em>mod</em>;</li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4712 <li><b><code>-i</code>: </b> enters interactive mode after running <em>script</em>;</li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4713 <li><b><code>-v</code>: </b> prints version information;</li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4714 <li><b><code>-E</code>: </b> ignores environment variables;</li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4715 <li><b><code>--</code>: </b> stops handling options;</li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4716 <li><b><code>-</code>: </b> executes <code>stdin</code> as a file and stops handling options.</li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4717 </ul><p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4718 After handling its options, <code>lua</code> runs the given <em>script</em>.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4719 When called without arguments,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4720 <code>lua</code> behaves as <code>lua -v -i</code>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4721 when the standard input (<code>stdin</code>) is a terminal,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4722 and as <code>lua -</code> otherwise.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4723
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4724
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4725 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4726 When called without option <code>-E</code>,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4727 the interpreter checks for an environment variable <a name="pdf-LUA_INIT_5_3"><code>LUA_INIT_5_3</code></a>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4728 (or <a name="pdf-LUA_INIT"><code>LUA_INIT</code></a> if the versioned name is not defined)
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4729 before running any argument.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4730 If the variable content has the format <code>@<em>filename</em></code>,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4731 then <code>lua</code> executes the file.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4732 Otherwise, <code>lua</code> executes the string itself.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4733
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4734
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4735 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4736 When called with option <code>-E</code>,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4737 besides ignoring <code>LUA_INIT</code>,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4738 Lua also ignores
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4739 the values of <code>LUA_PATH</code> and <code>LUA_CPATH</code>,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4740 setting the values of
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4741 <a href="#pdf-package.path"><code>package.path</code></a> and <a href="#pdf-package.cpath"><code>package.cpath</code></a>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4742 with the default paths defined in <code>luaconf.h</code>.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4743
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4744
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4745 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4746 All options are handled in order, except <code>-i</code> and <code>-E</code>.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4747 For instance, an invocation like
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4748
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4749 <pre>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4750 $ lua -e'a=1' -e 'print(a)' script.lua
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4751 </pre><p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4752 will first set <code>a</code> to 1, then print the value of <code>a</code>,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4753 and finally run the file <code>script.lua</code> with no arguments.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4754 (Here <code>$</code> is the shell prompt. Your prompt may be different.)
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4755
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4756
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4757 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4758 Before running any code,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4759 <code>lua</code> collects all command-line arguments
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4760 in a global table called <code>arg</code>.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4761 The script name goes to index 0,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4762 the first argument after the script name goes to index 1,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4763 and so on.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4764 Any arguments before the script name
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4765 (that is, the interpreter name plus its options)
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4766 go to negative indices.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4767 For instance, in the call
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4768
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4769 <pre>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4770 $ lua -la b.lua t1 t2
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4771 </pre><p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4772 the table is like this:
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4773
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4774 <pre>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4775 arg = { [-2] = "lua", [-1] = "-la",
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4776 [0] = "b.lua",
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4777 [1] = "t1", [2] = "t2" }
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4778 </pre><p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4779 If there is no script in the call,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4780 the interpreter name goes to index 0,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4781 followed by the other arguments.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4782 For instance, the call
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4783
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4784 <pre>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4785 $ lua -e "print(arg[1])"
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4786 </pre><p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4787 will print "<code>-e</code>".
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4788 If there is a script,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4789 the script is called with parameters
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4790 <code>arg[1]</code>, ···, <code>arg[#arg]</code>.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4791 (Like all chunks in Lua,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4792 the script is compiled as a vararg function.)
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4793
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4794
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4795 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4796 In interactive mode,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4797 Lua repeatedly prompts and waits for a line.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4798 After reading a line,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4799 Lua first try to interpret the line as an expression.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4800 If it succeeds, it prints its value.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4801 Otherwise, it interprets the line as a statement.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4802 If you write an incomplete statement,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4803 the interpreter waits for its completion
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4804 by issuing a different prompt.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4805
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4806
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4807 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4808 In case of unprotected errors in the script,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4809 the interpreter reports the error to the standard error stream.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4810 If the error object is not a string but
429 e3a6d9dbd694 rename __tostring to __to_string Franklin Schmidt <fschmidt@gmail.com> parents: 428 diff changeset	4811 has a metamethod <code>__to_string</code>,
371 e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4812 the interpreter calls this metamethod to produce the final message.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4813 Otherwise, the interpreter converts the error object to a string
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4814 and adds a stack traceback to it.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4815
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4816
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4817 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4818 When finishing normally,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4819 the interpreter closes its main Lua state
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4820 (see <a href="#lua_close"><code>lua_close</code></a>).
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4821 The script can avoid this step by
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4822 calling <a href="#pdf-os.exit"><code>os.exit</code></a> to terminate.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4823
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4824
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4825 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4826 To allow the use of Lua as a
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4827 script interpreter in Unix systems,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4828 the standalone interpreter skips
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4829 the first line of a chunk if it starts with <code>#</code>.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4830 Therefore, Lua scripts can be made into executable programs
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4831 by using <code>chmod +x</code> and the <code>#!</code> form,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4832 as in
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4833
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4834 <pre>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4835 #!/usr/local/bin/lua
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4836 </pre><p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4837 (Of course,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4838 the location of the Lua interpreter may be different in your machine.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4839 If <code>lua</code> is in your <code>PATH</code>,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4840 then
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4841
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4842 <pre>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4843 #!/usr/bin/env lua
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4844 </pre><p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4845 is a more portable solution.)
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4846
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4847
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4848
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4849 <h1>8 – <a name="8">Incompatibilities with the Previous Version</a></h1>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4850
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4851 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4852 Here we list the incompatibilities that you may find when moving a program
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4853 from Lua 5.2 to Lua 5.3.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4854 You can avoid some incompatibilities by compiling Lua with
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4855 appropriate options (see file <code>luaconf.h</code>).
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4856 However,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4857 all these compatibility options will be removed in the future.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4858
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4859
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4860 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4861 Lua versions can always change the C API in ways that
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4862 do not imply source-code changes in a program,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4863 such as the numeric values for constants
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4864 or the implementation of functions as macros.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4865 Therefore,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4866 you should not assume that binaries are compatible between
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4867 different Lua versions.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4868 Always recompile clients of the Lua API when
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4869 using a new version.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4870
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4871
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4872 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4873 Similarly, Lua versions can always change the internal representation
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4874 of precompiled chunks;
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4875 precompiled chunks are not compatible between different Lua versions.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4876
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4877
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4878 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4879 The standard paths in the official distribution may
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4880 change between versions.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4881
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4882
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4883
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4884 <h2>8.1 – <a name="8.1">Changes in the Language</a></h2>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4885 <ul>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4886
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4887 <li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4888 The main difference between Lua 5.2 and Lua 5.3 is the
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4889 introduction of an integer subtype for numbers.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4890 Although this change should not affect "normal" computations,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4891 some computations
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4892 (mainly those that involve some kind of overflow)
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4893 can give different results.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4894
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4895
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4896 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4897 You can fix these differences by forcing a number to be a float
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4898 (in Lua 5.2 all numbers were float),
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4899 in particular writing constants with an ending <code>.0</code>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4900 or using <code>x = x + 0.0</code> to convert a variable.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4901 (This recommendation is only for a quick fix
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4902 for an occasional incompatibility;
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4903 it is not a general guideline for good programming.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4904 For good programming,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4905 use floats where you need floats
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4906 and integers where you need integers.)
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4907 </li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4908
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4909 <li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4910 The conversion of a float to a string now adds a <code>.0</code> suffix
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4911 to the result if it looks like an integer.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4912 (For instance, the float 2.0 will be printed as <code>2.0</code>,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4913 not as <code>2</code>.)
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4914 You should always use an explicit format
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4915 when you need a specific format for numbers.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4916
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4917
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4918 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4919 (Formally this is not an incompatibility,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4920 because Lua does not specify how numbers are formatted as strings,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4921 but some programs assumed a specific format.)
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4922 </li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4923
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4924 <li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4925 The generational mode for the garbage collector was removed.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4926 (It was an experimental feature in Lua 5.2.)
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4927 </li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4928
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4929 </ul>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4930
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4931
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4932
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4933
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4934 <h2>8.2 – <a name="8.2">Changes in the Libraries</a></h2>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4935 <ul>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4936
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4937 <li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4938 The <code>bit32</code> library has been deprecated.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4939 It is easy to require a compatible external library or,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4940 better yet, to replace its functions with appropriate bitwise operations.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4941 (Keep in mind that <code>bit32</code> operates on 32-bit integers,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4942 while the bitwise operators in standard Lua operate on 64-bit integers.)
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4943 </li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4944
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4945 <li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4946 The Table library now respects metamethods
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4947 for setting and getting elements.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4948 </li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4949
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4950 <li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4951 The <a href="#pdf-ipairs"><code>ipairs</code></a> iterator now respects metamethods and
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4952 its <code>__ipairs</code> metamethod has been deprecated.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4953 </li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4954
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4955 <li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4956 Option names in <a href="#pdf-io.read"><code>io.read</code></a> do not have a starting '<code>*</code>' anymore.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4957 For compatibility, Lua will continue to ignore this character.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4958 </li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4959
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4960 <li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4961 The following functions were deprecated in the mathematical library:
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4962 <code>atan2</code>, <code>cosh</code>, <code>sinh</code>, <code>tanh</code>, <code>pow</code>,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4963 <code>frexp</code>, and <code>ldexp</code>.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4964 You can replace <code>math.pow(x,y)</code> with <code>x^y</code>;
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4965 you can replace <code>math.atan2</code> with <code>math.atan</code>,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4966 which now accepts one or two parameters;
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4967 you can replace <code>math.ldexp(x,exp)</code> with <code>x * 2.0^exp</code>.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4968 For the other operations,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4969 you can either use an external library or
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4970 implement them in Lua.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4971 </li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4972
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4973 <li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4974 The searcher for C loaders used by <a href="#pdf-require"><code>require</code></a>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4975 changed the way it handles versioned names.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4976 Now, the version should come after the module name
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4977 (as is usual in most other tools).
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4978 For compatibility, that searcher still tries the old format
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4979 if it cannot find an open function according to the new style.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4980 (Lua 5.2 already worked that way,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4981 but it did not document the change.)
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4982 </li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4983
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4984 </ul>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4985
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4986
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4987
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4988
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4989 <h2>8.3 – <a name="8.3">Changes in the API</a></h2>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4990
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4991
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4992 <ul>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4993
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4994 <li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4995 Continuation functions now receive as parameters what they needed
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4996 to get through <code>lua_getctx</code>,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4997 so <code>lua_getctx</code> has been removed.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4998 Adapt your code accordingly.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	4999 </li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5000
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5001 <li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5002 Function <a href="#lua_dump"><code>lua_dump</code></a> has an extra parameter, <code>strip</code>.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5003 Use 0 as the value of this parameter to get the old behavior.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5004 </li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5005
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5006 <li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5007 Functions to inject/project unsigned integers
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5008 (<code>lua_pushunsigned</code>, <code>lua_tounsigned</code>, <code>lua_tounsignedx</code>,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5009 <code>luaL_checkunsigned</code>, <code>luaL_optunsigned</code>)
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5010 were deprecated.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5011 Use their signed equivalents with a type cast.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5012 </li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5013
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5014 <li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5015 Macros to project non-default integer types
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5016 (<code>luaL_checkint</code>, <code>luaL_optint</code>, <code>luaL_checklong</code>, <code>luaL_optlong</code>)
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5017 were deprecated.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5018 Use their equivalent over <a href="#lua_Integer"><code>lua_Integer</code></a> with a type cast
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5019 (or, when possible, use <a href="#lua_Integer"><code>lua_Integer</code></a> in your code).
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5020 </li>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5021
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5022 </ul>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5023
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5024
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5025
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5026
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5027 <h1>9 – <a name="9">The Complete Syntax of Lua</a></h1>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5028
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5029 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5030 Here is the complete syntax of Lua in extended BNF.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5031 As usual in extended BNF,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5032 {A} means 0 or more As,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5033 and [A] means an optional A.
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5034 (For operator precedences, see <a href="#3.4.8">§3.4.8</a>;
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5035 for a description of the terminals
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5036 Name, Numeral,
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5037 and LiteralString, see <a href="#3.1">§3.1</a>.)
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5038
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5039
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5040
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5041
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5042 <pre>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5043
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5044 chunk ::= block
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5045
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5046 block ::= {stat} [retstat]
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5047
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5048 stat ::= ‘<b>;</b>’ \|
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5049 varlist ‘<b>=</b>’ explist \|
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5050 functioncall \|
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5051 label \|
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5052 <b>break</b> \|
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5053 <b>goto</b> Name \|
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5054 <b>do</b> block <b>end</b> \|
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5055 <b>while</b> exp <b>do</b> block <b>end</b> \|
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5056 <b>repeat</b> block <b>until</b> exp \|
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5057 <b>if</b> exp <b>then</b> block {<b>elseif</b> exp <b>then</b> block} [<b>else</b> block] <b>end</b> \|
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5058 <b>for</b> Name ‘<b>=</b>’ exp ‘<b>,</b>’ exp [‘<b>,</b>’ exp] <b>do</b> block <b>end</b> \|
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5059 <b>for</b> namelist <b>in</b> explist <b>do</b> block <b>end</b> \|
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5060 <b>function</b> funcname funcbody \|
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5061 <b>local</b> <b>function</b> Name funcbody \|
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5062 <b>local</b> namelist [‘<b>=</b>’ explist]
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5063
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5064 retstat ::= <b>return</b> [explist] [‘<b>;</b>’]
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5065
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5066 label ::= ‘<b>::</b>’ Name ‘<b>::</b>’
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5067
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5068 funcname ::= Name {‘<b>.</b>’ Name} [‘<b>:</b>’ Name]
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5069
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5070 varlist ::= var {‘<b>,</b>’ var}
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5071
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5072 var ::= Name \| prefixexp ‘<b>[</b>’ exp ‘<b>]</b>’ \| prefixexp ‘<b>.</b>’ Name
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5073
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5074 namelist ::= Name {‘<b>,</b>’ Name}
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5075
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5076 explist ::= exp {‘<b>,</b>’ exp}
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5077
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5078 exp ::= <b>nil</b> \| <b>false</b> \| <b>true</b> \| Numeral \| LiteralString \| ‘<b>...</b>’ \| functiondef \|
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5079 prefixexp \| tableconstructor \| exp binop exp \| unop exp
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5080
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5081 prefixexp ::= var \| functioncall \| ‘<b>(</b>’ exp ‘<b>)</b>’
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5082
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5083 functioncall ::= prefixexp args \| prefixexp ‘<b>:</b>’ Name args
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5084
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5085 args ::= ‘<b>(</b>’ [explist] ‘<b>)</b>’ \| tableconstructor \| LiteralString
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5086
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5087 functiondef ::= <b>function</b> funcbody
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5088
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5089 funcbody ::= ‘<b>(</b>’ [parlist] ‘<b>)</b>’ block <b>end</b>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5090
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5091 parlist ::= namelist [‘<b>,</b>’ ‘<b>...</b>’] \| ‘<b>...</b>’
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5092
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5093 tableconstructor ::= ‘<b>{</b>’ [fieldlist] ‘<b>}</b>’
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5094
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5095 fieldlist ::= field {fieldsep field} [fieldsep]
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5096
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5097 field ::= ‘<b>[</b>’ exp ‘<b>]</b>’ ‘<b>=</b>’ exp \| Name ‘<b>=</b>’ exp \| exp
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5098
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5099 fieldsep ::= ‘<b>,</b>’ \| ‘<b>;</b>’
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5100
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5101 binop ::= ‘<b>+</b>’ \| ‘<b>-</b>’ \| ‘<b>*</b>’ \| ‘<b>/</b>’ \| ‘<b>//</b>’ \| ‘<b>^</b>’ \| ‘<b>%</b>’ \|
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5102 ‘<b>&</b>’ \| ‘<b>~</b>’ \| ‘<b>\|</b>’ \| ‘<b>>></b>’ \| ‘<b><<</b>’ \| ‘<b>..</b>’ \|
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5103 ‘<b><</b>’ \| ‘<b><=</b>’ \| ‘<b>></b>’ \| ‘<b>>=</b>’ \| ‘<b>==</b>’ \| ‘<b>~=</b>’ \|
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5104 <b>and</b> \| <b>or</b>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5105
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5106 unop ::= ‘<b>-</b>’ \| <b>not</b> \| ‘<b>#</b>’ \| ‘<b>~</b>’
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5107
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5108 </pre>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5109
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5110 <p>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5111
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5112
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5113
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5114
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5115
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5116
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5117
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5118
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5119 <HR>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5120 <SMALL CLASS="footer">
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5121 Last update:
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5122 Fri Jan 16 00:58:20 BRST 2015
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5123 </SMALL>
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5124 <!--
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5125 Last change: minor edit
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5126 -->
e01cddba3433 add manual.html as copy of Lua 5.3 Reference Manual Franklin Schmidt <fschmidt@gmail.com> parents: diff changeset	5127
372 f08cefa4594c start editing manual Franklin Schmidt <fschmidt@gmail.com> parents: 371 diff changeset	5128 </div>
386 db23f654f87d make all of website use luan Franklin Schmidt <fschmidt@gmail.com> parents: 382 diff changeset	5129
391 2f5cc9c2cbf0 replace Html.simply_html_page with simply_html_head and simply_html_body_bottom Franklin Schmidt <fschmidt@gmail.com> parents: 389 diff changeset	5130 <% Html.simply_html_body_bottom() %>
2f5cc9c2cbf0 replace Html.simply_html_page with simply_html_head and simply_html_body_bottom Franklin Schmidt <fschmidt@gmail.com> parents: 389 diff changeset	5131 </body>
2f5cc9c2cbf0 replace Html.simply_html_page with simply_html_head and simply_html_body_bottom Franklin Schmidt <fschmidt@gmail.com> parents: 389 diff changeset	5132 </html>
2f5cc9c2cbf0 replace Html.simply_html_page with simply_html_head and simply_html_body_bottom Franklin Schmidt <fschmidt@gmail.com> parents: 389 diff changeset	5133 <%
386 db23f654f87d make all of website use luan Franklin Schmidt <fschmidt@gmail.com> parents: 382 diff changeset	5134 end
503 92c3d22745b8 make _ENV optional Franklin Schmidt <fschmidt@gmail.com> parents: 502 diff changeset	5135
92c3d22745b8 make _ENV optional Franklin Schmidt <fschmidt@gmail.com> parents: 502 diff changeset	5136 return M

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