Embed Lua example

average.lua

avg, sum = average(10, 20, 30, 40,  50)

print("The average is ", avg)
print("The sum is ", sum)
print("Versioin is ", VERSION)

main.cpp

#include <stdio.h>
#include <stdlib.h>

#include "lua.h"
#include "lualib.h"
#include "lauxlib.h"

/* The function we'll call from the lua script */
static int average(lua_State *L)
{
	/* get number of arguments */
	int n = lua_gettop(L);
	double sum = 0;
	int i;

	/* loop through each argument */
	for (i = 1; i <= n; i++)
	{
		if (!lua_isnumber(L, i)) 
		{
			lua_pushstring(L, "Incorrect argument to 'average'");
			lua_error(L);
		}

		/* total the arguments */
		sum += lua_tonumber(L, i);
	}

	/* push the average */
	lua_pushnumber(L, sum / n);

	/* push the sum */
	lua_pushnumber(L, sum);

	/* return the number of results */
	return 2;
}

/* the Lua interpreter */
lua_State* L;

#define VERSION "0.7"

int main ( int argc, char *argv[] )
{
	int sum;

	/* initialize Lua */
	L = luaL_newstate();
	luaL_openlibs(L);

	lua_pushstring(L, VERSION);
	lua_setglobal(L, "VERSION");

	lua_register(L, "average", average);
	luaL_dofile(L, "average.lua");

	/* cleanup Lua */
	lua_close(L);

	return 0;
}