functional.hpp

#ifndef ENTT_STL_FUNCTIONAL_HPP
#define ENTT_STL_FUNCTIONAL_HPP

#if __has_include(<entt/ext/stl/functional.hpp>)
#    include <entt/ext/stl/functional.hpp>
#else
#    include <functional>
#    include <version>
#    include "../config/config.h"
 
namespace entt::stl {
 
using std::equal_to;
using std::function;
using std::hash;
using std::invoke;
using std::less;
 
} // namespace entt::stl
 
#    ifndef ENTT_FORCE_STL
#        if defined(__cpp_lib_ranges)
#            define ENTT_HAS_IDENTITY
namespace entt::stl {
 
using std::identity;
 
} // namespace entt::stl
#        endif
#    endif
 
#    ifndef ENTT_HAS_IDENTITY
#        include <utility>
 
namespace entt::stl {
 
struct identity {
    using is_transparent = void;
 
    template<typename Type>
    [[nodiscard]] constexpr Type &&operator()(Type &&value) const noexcept {
        return std::forward<Type>(value);
    }
};
 
} // namespace entt::stl
#    endif
 
#endif
 
#undef ENTT_HAS_IDENTITY
 
#endif