added Lua to C example

libogc2/lualib/lua/script.lua

@@ -6,5 +6,10 @@ for i = 1, #foo do
   print(i, foo[i])
   x = x + foo[i]
 end
+
+io.write("Asking C to compute average and sum and check the equality\n")
+avg, sum = average(unpack(foo));
+
+print(x == sum)
 io.write("Returning data back to C\n");
-return x
+return sum

libogc2/lualib/source/main.c

@@ -38,7 +38,7 @@ static void reset_cb(u32 irq, void* ctx) {
 }
 
 lua_State * LUA_Init() {
-	
+
 	lua_State * L;
 	L = luaL_newstate();
 
@@ -48,6 +48,30 @@ lua_State * LUA_Init() {
 	return L;
 }
 
+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++)
+	{
+		/* 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;
+}
+
 int main(int argc, char *argv[]) {
 
 	int is_connected = 0;
@@ -105,6 +129,9 @@ int main(int argc, char *argv[]) {
 				break;
 			}
 
+			/* register our function */
+			lua_register(L, "average", average);
+
 			lua_newtable(L);
 			for (int i = 1; i <= 5; i++) {
 				lua_pushnumber(L, i);   /* Push the table index */