cache.hpp

template <typename R, typename... Args>
std::function<R(Args...)> cache(R(*func) (Args...))
{
	auto result_map = std::make_shared<std::map<std::tuple<Args...>, R>>();

	return ([=](Args... args){
		std::tuple<Args...> t(args...);
		if (result_map->find(t) == result_map->end())
			(*result_map)[t] = func(args...);

		return (*result_map)[t];
	});
}

template <typename R, typename...  Args>
std::function<R(Args...)> sugar(R(*func)(Args...), bool needClear = false)
{
	using function_type = std::function<R(Args...)>;
	static std::unordered_map<decltype(func), function_type> functor_map;

	if (needClear)
		return functor_map[func] = cache(func);

	if (functor_map.find(func) == functor_map.end())
		functor_map[func] = cache(func);

	return functor_map[func];
}


/*test code
size_t fibonacci(size_t n)
{
return (n < 2) ? n : sugar(fibonacci2)(n - 1) + sugar(fibonacci2)(n - 2);
}


*/