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@@ -1,137 +1,161 @@ -.\" lua.man,v 1.3 2000/09/04 21:41:28 lhf Exp -.TH LUA 1 "2000/09/04 21:41:28" +.\" lua.man,v 1.8 2003/04/02 00:05:20 lhf Exp +.TH LUA 1 "2003/04/02 00:05:20" .SH NAME lua \- Lua interpreter .SH SYNOPSIS .B lua [ -.I arguments +.I options +] +[ +.I script +[ +.I args +] ] .SH DESCRIPTION .B lua is the stand-alone Lua interpreter. It loads and executes Lua programs, either in textual source form or -in precompiled binary form, -as output by +in precompiled binary form. +(Precompiled binaries are output by .BR luac , -the Lua compiler. +the Lua compiler.) .B lua can be used as a batch interpreter and also interactively. .LP -The -.I arguments -can be options, assignments, or filenames, -and are processed in order, -from left to right. +The given +.I options +(see below) +are executed and then +the Lua program in file +.I script +is loaded and executed. +The given +.I args +are available to +.I script +as strings in a global table named +.BR arg . +If these arguments contain spaces or other characters special to the shell, +then they should be quoted +(but note that the quotes will be removed by the shell). +The arguments in +.B arg +start at 0, +which contains the string +.RI ` script '. +The index of the last argument is stored in +.BR "arg.n" . +The arguments given in the command line before +.IR script , +including the name of the interpreter, +are available in negative indices in +.BR arg . +.LP +At the very start, +before even handling the command line, +.B lua +executes the contents of the environment variable +.BR LUA_INIT , +if it is defined. +If the value of +.B LUA_INIT +is of the form +.RI `@ filename ', +then +.I filename +is executed. +Otherwise, the string is assumed to be a Lua statement and is executed. .LP Options start with .B \- and are described below. -.LP -An assignment is an argument of the form -.BR a=b , -which assigns the string -.RB ` b ' -to the global variable -.BR a . -Note that no quotes are needed around the string if it does not contain spaces -or other characters special to the shell. -This is for convenience only. -(In general, -you should be careful when using quotes and spaces on the command line -because they are usually handled by the shell.) -.LP -If the argument is neither an option nor an assignment, -then it is assumed to be a filename, -which is then loaded and executed. +You can use +.B "\--" +to signal the end of options. .LP If no arguments are given, then .B "\-v \-i" is assumed when the standard input is a terminal; otherwise, -.B \- +.B "\-" is assumed. +.LP +In interactive mode, +.B lua +prompts the user, +reads lines from the standard input, +and executes them as they are read. +If a line does not contain a complete statement, +then a secondary prompt is displayed and +lines are read until a complete statement is formed or +a syntax error is found. +So, one way to interrupt the reading of an incomplete statement is +to force a syntax error: +adding a +.B `;' +in the middle of a statement is a sure way of forcing a syntax error +(except inside multiline strings and comments; these must be closed explicitly). +If a line starts with +.BR `=' , +then +.B lua +displays the values of all the expressions in the remainder of the +line. The expressions must be separated by commas. +The primary prompt is the value of the global variable +.BR _PROMPT , +if this value is a string; +otherwise, the default prompt is used. +Similarly, the secondary prompt is the value of the global variable +.BR _PROMPT2 . +So, +to change the prompts, +set the corresponding variable to a string of your choice. +You can do that after calling the interpreter +or on the command line with +.BR "_PROMPT" "=\'lua: \'" , +for example. +(Note the need for quotes, because the string contains a space.) +The default prompts are ``> '' and ``>> ''. .SH OPTIONS .TP .B \- -load the standard input as a file, +load and execute the standard input as a file, that is, not interactively, even when the standard input is a terminal. .TP -.B \-c -close Lua before exiting. -.TP .BI \-e " stat" execute statement .IR stat . -You will need to quote +You need to quote .I stat -if it contains spaces or quotes. -.TP -.BI \-f " file" -collect all remaining arguments as strings into a global table named -.B arg -and then execute -.IR file . -The arguments in -.B arg -start at 0, -which contains the string -.RI ` file '. -The index of the last argument is stored in -.BR "arg.n" . +if it contains spaces, quotes, +or other characters special to the shell. .TP .B \-i -enter interactive mode, -displaying a prompt. -In this mode, -.B lua -reads lines from the standard input and executes them as they are read. -Each line must contain a complete statement. -To span a statement across several lines, end each line with a backslash -.BR `\e' . -The prompt shown is the value of the global variable -.BR _PROMPT , -if this value is a string. -So, -to change the prompt, -set -.B _PROMPT -to a string of your choice. -You can do that after calling the interpreter -or on the command line with -.BR "_PROMPT=\'lua: \'" , -for example. -(Note the need for quotes, because the string contains a space.) -The default prompt is ``> ''. -.TP -.B \-q -enter interactive mode, -but without displaying a prompt. +enter interactive mode after +.I script +is executed. .TP -.BI \-s n -set the stack size to -.IB n . -If present, -this must be the first option. -Note that -.I n -is in the same argument as -.BR -s . -For example, -to specify a stack size of 2000, -use -.BR -s2000 . +.BI \-l " file" +call +.BI require( file ) +before executing +.IR script. +Typically used to load libraries +(hence the letter +.IR l ). .TP .B \-v -print version information. +show version information. .SH "SEE ALSO" .BR luac (1) .br -http://www.tecgraf.puc-rio.br/lua/ +http://www.lua.org/ .SH DIAGNOSTICS Error messages should be self explanatory. .SH AUTHORS |