By Tony and Paige at www.tonyandpaige.com

Lua is a light-weight scripting language designed to extend existing C and C++ programs. Unfortunately, there are very few online tutorials covering this language. I learned how it works mainly by reading the source, and studying the programs included with the distribution. Hopefully, this page will make learning Lua a little easier for those following in my footsteps.

First, you need to download Lua. You can get the source from the Lua download page. If you're using Windows and would prefer precompiled binaries, you can check out Philippe Lhoste's Lua Page or scroll to the bottom of this page.

Now we need to install Lua. On Linux you should be able to just extract the files then type "make" and "make install" as root. See the INSTALL file if you need more help. On Windows download the binaries below and unzip them to a folder like "C:\Program Files\Lua-5.0".

Everything should be ready to go on Linux, but on Windows we'll need to configure Visual C++ so it can find the Lua files.

1. Open Visual C++ then go to Tools, Options.
2. Click the directories tab.
3. Choose "Include files" and add a new path "C:\Program Files\Lua-5.0".
4. Now choose "Library files" and add the same path.

You're now ready to compile your first Lua enabled C++ program.

Your first program with Lua

This program is short and straight forward, but I'll run through what's happening just in case it's not clear.

1. A pointer to our Lua interpreter is created by calling lua_open().
2. Lua libraries are loaded with lua_baselibopen(). This provides simple functions like print.
3. Our script is executed with lua_dofile(). This reads the file and runs the script.
4. Finally, Lua is closed properly with lua_close().

Save this file as luatest.cpp. If you'd like to use straight C instead of C++, just name the file luatest.c and remove the extern "C".

#include <stdio.h>

extern "C" {
	#include "lua.h"
	#include "lualib.h"
	#include "lauxlib.h"
}

/* the Lua interpreter */
lua_State* L;

int main ( int argc, char *argv[] )
{
	/* initialize Lua */
	L = lua_open();

	/* load Lua base libraries */
	lua_baselibopen(L);

	/* run the script */
	lua_dofile(L, "test.lua");

	/* cleanup Lua */
	lua_close(L);

	return 0;
}
      

-- simple test

print "Hello, World!"

g++ luatest.cpp -llua -llualib -o luatest

./luatest