concepts

// -*- C++ -*-
#ifndef _EZCXX_CONCEPTS
#define _EZCXX_CONCEPTS

#include <type_traits>

#pragma clang system_header

namespace std {

template<class _Tp, class _Up>
concept same_as = is_same<_Tp, _Up>::value && is_same<_Up, _Tp>::value;

template<class _From, class _To>
concept convertible_to =
    is_convertible_v<_From, _To> &&
    requires { static_cast<_To>(std::declval<_From>()); };

template <class _Dp, class _Bp>
concept derived_from =
    is_base_of_v<_Bp, _Dp> &&
    is_convertible_v<const volatile _Dp*, const volatile _Bp*>;

template<class _Tp>
concept destructible = is_nothrow_destructible_v<_Tp>;

template<class _Tp, class... _Args>
concept constructible_from =
    destructible<_Tp> && is_constructible_v<_Tp, _Args...>;

template<class _Tp>
concept integral = is_integral_v<_Tp>;

template<class _Tp>
concept signed_integral = integral<_Tp> && is_signed_v<_Tp>;

template<class _Tp>
concept unsigned_integral = integral<_Tp> && !signed_integral<_Tp>;

template<class _Tp>
concept floating_point = is_floating_point_v<_Tp>;

template<class _Tp>
concept move_constructible =
    constructible_from<_Tp, _Tp> && std::convertible_to<_Tp, _Tp>;

template<class _Tp>
concept copy_constructible =
    move_constructible<_Tp> &&
    constructible_from<_Tp, _Tp&> && convertible_to<_Tp&, _Tp> &&
    constructible_from<_Tp, const _Tp&> && convertible_to<const _Tp&, _Tp> &&
    constructible_from<_Tp, const _Tp> && convertible_to<const _Tp, _Tp>;

} // namespace std

#endif // _EZCXX_CONCEPTS