deps/lua/doc/lua.1

   1 .\" $Id: lua.man,v 1.11 2006/01/06 16:03:34 lhf Exp $
   2 .TH LUA 1 "$Date: 2006/01/06 16:03:34 $"
   3 .SH NAME
   4 lua \- Lua interpreter
   5 .SH SYNOPSIS
   6 .B lua
   7 [
   8 .I options
   9 ]
  10 [
  11 .I script
  12 [
  13 .I args
  14 ]
  15 ]
  16 .SH DESCRIPTION
  17 .B lua
  18 is the stand-alone Lua interpreter.
  19 It loads and executes Lua programs,
  20 either in textual source form or
  21 in precompiled binary form.
  22 (Precompiled binaries are output by
  23 .BR luac ,
  24 the Lua compiler.)
  25 .B lua
  26 can be used as a batch interpreter and also interactively.
  27 .LP
  28 The given
  29 .I options
  30 (see below)
  31 are executed and then
  32 the Lua program in file
  33 .I script
  34 is loaded and executed.
  35 The given
  36 .I args
  37 are available to
  38 .I script
  39 as strings in a global table named
  40 .BR arg .
  41 If these arguments contain spaces or other characters special to the shell,
  42 then they should be quoted
  43 (but note that the quotes will be removed by the shell).
  44 The arguments in
  45 .B arg
  46 start at 0,
  47 which contains the string
  48 .RI ' script '.
  49 The index of the last argument is stored in
  50 .BR arg.n .
  51 The arguments given in the command line before
  52 .IR script ,
  53 including the name of the interpreter,
  54 are available in negative indices in
  55 .BR arg .
  56 .LP
  57 At the very start,
  58 before even handling the command line,
  59 .B lua
  60 executes the contents of the environment variable
  61 .BR LUA_INIT ,
  62 if it is defined.
  63 If the value of
  64 .B LUA_INIT
  65 is of the form
  66 .RI '@ filename ',
  67 then
  68 .I filename
  69 is executed.
  70 Otherwise, the string is assumed to be a Lua statement and is executed.
  71 .LP
  72 Options start with
  73 .B '\-'
  74 and are described below.
  75 You can use
  76 .B "'\--'"
  77 to signal the end of options.
  78 .LP
  79 If no arguments are given,
  80 then
  81 .B "\-v \-i"
  82 is assumed when the standard input is a terminal;
  83 otherwise,
  84 .B "\-"
  85 is assumed.
  86 .LP
  87 In interactive mode,
  88 .B lua
  89 prompts the user,
  90 reads lines from the standard input,
  91 and executes them as they are read.
  92 If a line does not contain a complete statement,
  93 then a secondary prompt is displayed and
  94 lines are read until a complete statement is formed or
  95 a syntax error is found.
  96 So, one way to interrupt the reading of an incomplete statement is
  97 to force a syntax error:
  98 adding a
  99 .B ';'
 100 in the middle of a statement is a sure way of forcing a syntax error
 101 (except inside multiline strings and comments; these must be closed explicitly).
 102 If a line starts with
 103 .BR '=' ,
 104 then
 105 .B lua
 106 displays the values of all the expressions in the remainder of the
 107 line. The expressions must be separated by commas.
 108 The primary prompt is the value of the global variable
 109 .BR _PROMPT ,
 110 if this value is a string;
 111 otherwise, the default prompt is used.
 112 Similarly, the secondary prompt is the value of the global variable
 113 .BR _PROMPT2 .
 114 So,
 115 to change the prompts,
 116 set the corresponding variable to a string of your choice.
 117 You can do that after calling the interpreter
 118 or on the command line
 119 (but in this case you have to be careful with quotes
 120 if the prompt string contains a space; otherwise you may confuse the shell.)
 121 The default prompts are "> " and ">> ".
 122 .SH OPTIONS
 123 .TP
 124 .B \-
 125 load and execute the standard input as a file,
 126 that is,
 127 not interactively,
 128 even when the standard input is a terminal.
 129 .TP
 130 .BI \-e " stat"
 131 execute statement
 132 .IR stat .
 133 You need to quote
 134 .I stat
 135 if it contains spaces, quotes,
 136 or other characters special to the shell.
 137 .TP
 138 .B \-i
 139 enter interactive mode after
 140 .I script
 141 is executed.
 142 .TP
 143 .BI \-l " name"
 144 call
 145 .BI require(' name ')
 146 before executing
 147 .IR script .
 148 Typically used to load libraries.
 149 .TP
 150 .B \-v
 151 show version information.
 152 .SH "SEE ALSO"
 153 .BR luac (1)
 154 .br
 155 http://www.lua.org/
 156 .SH DIAGNOSTICS
 157 Error messages should be self explanatory.
 158 .SH AUTHORS
 159 R. Ierusalimschy,
 160 L. H. de Figueiredo,
 161 and
 162 W. Celes
 163 .\" EOF