Just for curiosity I wanted to try embedding a Lua script into a little C program and surprisingly it resulted in a pretty quick and easy task.
Lua provides C API and everything is done within a few lines of code.
Let’s assume that our Lua script just prints “hello world” once it is executed and contains also a function to be called later.
Save a file as “hello.lua” and fill in with:
print("Hello world!");
function foo()
print("Hi I am the foo function!");
end
Then create the C program that will run Lua ans save it as “embed_hello.c” with the following content:
#include <stdio.h>
#include "lua.h"
#include "lualib.h"
#include "lauxlib.h"
/* lua interpreter */
lua_State* l;
int main () {
int dofile;
/* initialize lua */
l = lua_open();
/* load lua libraries */
luaL_openlibs(l);
/* run the hello.lua script */
dofile = luaL_dofile(l, "hello.lua");
if (dofile == 0) {
/* call foo */
lua_getglobal(l,"foo");
lua_call(l,0,0);
}
else {
printf("Error, unable to run hello.lua\n");
}
/* cleanup Lua */
lua_close(l);
return 0;
}
Compile:
$ gcc -o embed_hello -Wall -L/opt/local/lib -I/opt/local/include \ -llua embed_hello.c
That’s all. This example works for OS X and Lua installed from macports. For other OSs and configurations just adapt the gcc command.
Execute it
$ ./embed_hello Hello world! Hi I am the foo function!