utility.hpp

#ifndef ENTT_CORE_UTILITY_HPP
#define ENTT_CORE_UTILITY_HPP
 
 
#include <utility>
#include "../config/config.h"
 
 
namespace entt {
 
 
struct identity {
    template<class Type>
    [[nodiscard]] constexpr Type && operator()(Type &&value) const ENTT_NOEXCEPT {
        return std::forward<Type>(value);
    }
};
 
 
template<typename Type, typename Class>
[[nodiscard]] constexpr auto overload(Type Class:: *member) ENTT_NOEXCEPT { return member; }
 
 
template<typename Func>
[[nodiscard]] constexpr auto overload(Func *func) ENTT_NOEXCEPT { return func; }
 
 
template<class... Func>
struct overloaded: Func... {
    using Func::operator()...;
};
 
 
template<class... Func>
overloaded(Func...) -> overloaded<Func...>;
 
 
template<class Func>
struct y_combinator {
    y_combinator(Func recursive):
        func{std::move(recursive)}
    {}
 
    template <class... Args>
    decltype(auto) operator()(Args &&... args) const {
        return func(*this, std::forward<Args>(args)...);
    }
 
    template <class... Args>
    decltype(auto) operator()(Args &&... args) {
        return func(*this, std::forward<Args>(args)...);
    }
 
private:
    Func func;
};
 
 
}
 
 
#endif