NAME¶
luac - Lua compiler
SYNOPSIS¶
luac [
options ] [
filenames ]
DESCRIPTION¶
luac is the Lua compiler. It translates programs written in the Lua
programming language into binary files that can be latter loaded and executed.
The main advantages of precompiling chunks are: faster loading, protecting
source code from user changes, and off-line syntax checking.
Pre-compiling does not imply faster execution because in Lua chunks are always
compiled into bytecodes before being executed.
luac simply allows those
bytecodes to be saved in a file for later execution.
luac produces a single output file containing the bytecodes for all
source files given. By default, the output file is named
luac.out, but
you can change this with the
-o option.
The binary files created by
luac are portable to all architectures with
the same word size. This means that binary files created on a 32-bit platform
(such as Intel) can be read without change in another 32-bit platform (such as
Sparc), even if the byte order (``endianness'') is different. On the other
hand, binary files created on a 16-bit platform cannot be read in a 32-bit
platform, nor vice-versa.
In the command line, you can mix text files containing Lua source and binary
files containing precompiled chunks. This is useful to combine several
precompiled chunks, even from different (but compatible) platforms, into a
single precompiled chunk.
You can use
- to indicate the standard input as a source file and
-- to signal the end of options (that is, all remaining arguments will
be treated as files even if they start with
-).
The internal format of the binary files produced by
luac is likely to
change when a new version of Lua is released. So, save the source files of all
Lua programs that you precompile.
OPTIONS¶
Options must be separate.
- -l
- produce a listing of the compiled bytecode for Lua's
virtual machine. Listing bytecodes is useful to learn about Lua's virtual
machine. If no files are given, then luac loads luac.out and
lists its contents.
- -o file
- output to file, instead of the default
luac.out. The output file may be a source file because all files
are loaded before the output file is written. Be careful not to overwrite
precious files.
- -p
- load files but do not generate any output file. Used mainly
for syntax checking and for testing precompiled chunks: corrupted files
will probably generate errors when loaded. Lua always performs a thorough
integrity test on precompiled chunks. Bytecode that passes this test is
completely safe, in the sense that it will not break the interpreter.
However, there is no guarantee that such code does anything sensible.
(None can be given, because the halting problem is unsolvable.) If no
files are given, then luac loads luac.out and tests its
contents. No messages are displayed if the file passes the integrity
test.
- -s
- strip debug information before writing the output file.
This saves some space in very large chunks, but if errors occur when
running these chunks, then the error messages may not contain the full
information they usually do (line numbers and names of locals are
lost).
- -v
- show version information.
FILES¶
- luac.out
- default output file
SEE ALSO¶
lua(1)
http://www.lua.org/
DIAGNOSTICS¶
Error messages should be self explanatory.
AUTHORS¶
L. H. de Figueiredo, R. Ierusalimschy and W. Celes
(lua@tecgraf.puc-rio.br)
