oh dear god, what have I done?

gistfile1.txt

void openCustomLibraries(lua_State* L) {
  //-------------------------
	// Define the map library for lua
	//-------------------------

	//push the initial table
	lua_newtable(L);

	lua_pushcfunction(L, [](lua_State* l) -> int {
		//require 4 parameters
		while (lua_gettop(l) < 4) {
			lua_pushnumber(l, -1);
		}

		Map::GetSingletonPtr()->Generate(
			lua_tonumber(l, 1),
			lua_tonumber(l, 2),
			lua_tonumber(l, 3),
			lua_tonumber(l, 4)
			);

		return 0;
	});
	lua_setfield(L, 1, "Generate");

	lua_pushcfunction(L, [](lua_State* l) -> int {
		Map::GetSingletonPtr()->Clear();
		return 0;
	});
	lua_setfield(L, 1, "Clear");

	lua_pushcfunction(L, [](lua_State* l) -> int {
		Map::GetSingletonPtr()->InsertLayer(lua_tonumber(l, 1), lua_tonumber(l, 2));
		return 0;
	});
	lua_setfield(L, 1, "InsertLayer");

	lua_pushcfunction(L, [](lua_State* l) -> int {
		Map::GetSingletonPtr()->DeleteLayer(lua_tonumber(l, 1));
		return 0;
	});
	lua_setfield(L, 1, "DeleteLayer");

	lua_pushcfunction(L, [](lua_State* l) -> int {
		int ret = Map::GetSingletonPtr()->SetTile(
			lua_tonumber(l, 1),
			lua_tonumber(l, 2),
			lua_tonumber(l, 3),
			lua_tonumber(l, 4)
			);
		lua_pushnumber(l, ret);
		return 1;
	});
	lua_setfield(L, 1, "SetTile");

	lua_pushcfunction(L, [](lua_State* l) -> int {
		int ret = Map::GetSingletonPtr()->SetTile(
			lua_tonumber(l, 1),
			lua_tonumber(l, 2),
			lua_tonumber(l, 3)
			);
		lua_pushnumber(l, ret);
		return 1;
	});
	lua_setfield(L, 1, "GetTile");

	lua_pushcfunction(L, [](lua_State* l) -> int {
		int ret = Map::GetSingletonPtr()->GetLayerCount();
		lua_pushnumber(l, ret);
		return 1;
	});
	lua_setfield(L, 1, "GetLayerCount");

	lua_pushcfunction(L, [](lua_State* l) -> int {
		int ret = Map::GetSingletonPtr()->GetWidth();
		lua_pushnumber(l, ret);
		return 1;
	});
	lua_setfield(L, 1, "GetWidth");

	lua_pushcfunction(L, [](lua_State* l) -> int {
		int ret = Map::GetSingletonPtr()->GetHeight();
		lua_pushnumber(l, ret);
		return 1;
	});
	lua_setfield(L, 1, "GetHeight");

	//finalize this library
	lua_setglobal(L, "map");
}