Function main

examples/source/usertype_var.cpp:12–49

int main() {
	sol::state lua;
	lua.open_libraries();
	lua.new_usertype<test>("test",
	     "direct",
	     sol::var(2),
	     "number",
	     sol::var(test::number),
	     "ref_number",
	     sol::var(std::ref(test::number)));

	int direct_value = lua["test"]["direct"];
	SOL_ASSERT(direct_value == 2);

	int number = lua["test"]["number"];
	SOL_ASSERT(number == 25);
	int ref_number = lua["test"]["ref_number"];
	SOL_ASSERT(ref_number == 25);

	test::number = 542;

	// number is its own memory: was passed by value
	// So does not change
	int number_again = lua["test"]["number"];
	SOL_ASSERT(number_again == 25);

	// ref_number is just test::number
	// passed through std::ref
	// so, it holds a reference
	// which can be updated
	int ref_number_again = lua["test"]["ref_number"];
	SOL_ASSERT(ref_number_again == 542);
	// be careful about referencing local variables,
	// if they go out of scope but are still reference
	// you'll suffer dangling reference bugs!

	return 0;
}