llvm-project/libcxx/include/concepts

452 lines
14 KiB
C++

// -*- C++ -*-
//===-------------------------- concepts ----------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#ifndef _LIBCPP_CONCEPTS
#define _LIBCPP_CONCEPTS
/*
concepts synopsis
namespace std {
// [concepts.lang], language-related concepts
// [concept.same], concept same_as
template<class T, class U>
concept same_as = see below;
// [concept.derived], concept derived_from
template<class Derived, class Base>
concept derived_from = see below;
// [concept.convertible], concept convertible_to
template<class From, class To>
concept convertible_to = see below;
// [concept.commonref], concept common_reference_with
template<class T, class U>
concept common_reference_with = see below;
// [concept.common], concept common_with
template<class T, class U>
concept common_with = see below;
// [concepts.arithmetic], arithmetic concepts
template<class T>
concept integral = see below;
template<class T>
concept signed_integral = see below;
template<class T>
concept unsigned_integral = see below;
template<class T>
concept floating_point = see below;
// [concept.assignable], concept assignable_from
template<class LHS, class RHS>
concept assignable_from = see below;
// [concept.swappable], concept swappable
namespace ranges {
inline namespace unspecified {
inline constexpr unspecified swap = unspecified;
}
}
template<class T>
concept swappable = see below;
template<class T, class U>
concept swappable_with = see below;
// [concept.destructible], concept destructible
template<class T>
concept destructible = see below;
// [concept.constructible], concept constructible_from
template<class T, class... Args>
concept constructible_from = see below;
// [concept.default.init], concept default_initializable
template<class T>
concept default_initializable = see below;
// [concept.moveconstructible], concept move_constructible
template<class T>
concept move_constructible = see below;
// [concept.copyconstructible], concept copy_constructible
template<class T>
concept copy_constructible = see below;
// [concept.equalitycomparable], concept equality_comparable
template<class T>
concept equality_comparable = see below;
template<class T, class U>
concept equality_comparable_with = see below;
// [concept.totallyordered], concept totally_ordered
template<class T>
concept totally_ordered = see below;
template<class T, class U>
concept totally_ordered_with = see below;
// [concepts.object], object concepts
template<class T>
concept movable = see below;
template<class T>
concept copyable = see below;
template<class T>
concept semiregular = see below;
template<class T>
concept regular = see below;
// [concepts.callable], callable concepts
// [concept.invocable], concept invocable
template<class F, class... Args>
concept invocable = see below;
// [concept.regularinvocable], concept regular_invocable
template<class F, class... Args>
concept regular_invocable = see below;
// [concept.predicate], concept predicate
template<class F, class... Args>
concept predicate = see below;
// [concept.relation], concept relation
template<class R, class T, class U>
concept relation = see below;
// [concept.equiv], concept equivalence_relation
template<class R, class T, class U>
concept equivalence_relation = see below;
// [concept.strictweakorder], concept strict_weak_order
template<class R, class T, class U>
concept strict_weak_order = see below;
}
*/
#include <__config>
#include <__functional_base>
#include <type_traits>
#include <utility>
#include <version>
#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
#pragma GCC system_header
#endif
_LIBCPP_PUSH_MACROS
#include <__undef_macros>
_LIBCPP_BEGIN_NAMESPACE_STD
#if _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_CONCEPTS)
// [concept.same]
template<class _Tp, class _Up>
concept __same_as_impl = _VSTD::_IsSame<_Tp, _Up>::value;
template<class _Tp, class _Up>
concept same_as = __same_as_impl<_Tp, _Up> && __same_as_impl<_Up, _Tp>;
// [concept.derived]
template<class _Dp, class _Bp>
concept derived_from =
is_base_of_v<_Bp, _Dp> &&
is_convertible_v<const volatile _Dp*, const volatile _Bp*>;
// [concept.convertible]
template<class _From, class _To>
concept convertible_to =
is_convertible_v<_From, _To> &&
requires(add_rvalue_reference_t<_From> (&__f)()) {
static_cast<_To>(__f());
};
// [concept.commonref]
template<class _Tp, class _Up>
concept common_reference_with =
same_as<common_reference_t<_Tp, _Up>, common_reference_t<_Up, _Tp>> &&
convertible_to<_Tp, common_reference_t<_Tp, _Up>> &&
convertible_to<_Up, common_reference_t<_Tp, _Up>>;
// [concept.common]
template<class _Tp, class _Up>
concept common_with =
same_as<common_type_t<_Tp, _Up>, common_type_t<_Up, _Tp>> &&
requires {
static_cast<common_type_t<_Tp, _Up>>(declval<_Tp>());
static_cast<common_type_t<_Tp, _Up>>(declval<_Up>());
} &&
common_reference_with<
add_lvalue_reference_t<const _Tp>,
add_lvalue_reference_t<const _Up>> &&
common_reference_with<
add_lvalue_reference_t<common_type_t<_Tp, _Up>>,
common_reference_t<
add_lvalue_reference_t<const _Tp>,
add_lvalue_reference_t<const _Up>>>;
// [concepts.arithmetic], arithmetic concepts
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>;
// [concept.assignable]
template<class _Lhs, class _Rhs>
concept assignable_from =
is_lvalue_reference_v<_Lhs> &&
common_reference_with<__make_const_lvalue_ref<_Lhs>, __make_const_lvalue_ref<_Rhs>> &&
requires (_Lhs __lhs, _Rhs&& __rhs) {
{ __lhs = _VSTD::forward<_Rhs>(__rhs) } -> same_as<_Lhs>;
};
// [concept.destructible]
template<class _Tp>
concept destructible = is_nothrow_destructible_v<_Tp>;
// [concept.constructible]
template<class _Tp, class... _Args>
concept constructible_from =
destructible<_Tp> && is_constructible_v<_Tp, _Args...>;
// [concept.default.init]
template<class _Tp>
concept __default_initializable = requires { ::new _Tp; };
template<class _Tp>
concept default_initializable = constructible_from<_Tp> &&
requires { _Tp{}; } && __default_initializable<_Tp>;
// [concept.moveconstructible]
template<class _Tp>
concept move_constructible =
constructible_from<_Tp, _Tp> && convertible_to<_Tp, _Tp>;
// [concept.copyconstructible]
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>;
// Whether a type is a class type or enumeration type according to the Core wording.
template<class _Tp>
concept __class_or_enum = is_class_v<_Tp> || is_union_v<_Tp> || is_enum_v<_Tp>;
// [concept.swappable]
namespace ranges::__swap {
// Deleted to inhibit ADL
template<class _Tp>
void swap(_Tp&, _Tp&) = delete;
// [1]
template<class _Tp, class _Up>
concept __unqualified_swappable_with =
(__class_or_enum<remove_cvref_t<_Tp>> || __class_or_enum<remove_cvref_t<_Up>>) &&
requires(_Tp&& __t, _Up&& __u) {
swap(_VSTD::forward<_Tp>(__t), _VSTD::forward<_Up>(__u));
};
struct __fn;
template<class _Tp, class _Up, size_t _Size>
concept __swappable_arrays =
!__unqualified_swappable_with<_Tp(&)[_Size], _Up(&)[_Size]> &&
extent_v<_Tp> == extent_v<_Up> &&
requires(_Tp(& __t)[_Size], _Up(& __u)[_Size], const __fn& __swap) {
__swap(__t[0], __u[0]);
};
template<class _Tp>
concept __exchangeable =
!__unqualified_swappable_with<_Tp&, _Tp&> &&
move_constructible<_Tp> &&
assignable_from<_Tp&, _Tp>;
struct __fn {
// 2.1 `S` is `(void)swap(E1, E2)`* if `E1` or `E2` has class or enumeration type and...
// *The name `swap` is used here unqualified.
template<class _Tp, class _Up>
requires __unqualified_swappable_with<_Tp, _Up>
constexpr void operator()(_Tp&& __t, _Up&& __u) const
noexcept(noexcept(swap(_VSTD::forward<_Tp>(__t), _VSTD::forward<_Up>(__u))))
{
swap(_VSTD::forward<_Tp>(__t), _VSTD::forward<_Up>(__u));
}
// 2.2 Otherwise, if `E1` and `E2` are lvalues of array types with equal extent and...
template<class _Tp, class _Up, size_t _Size>
requires __swappable_arrays<_Tp, _Up, _Size>
constexpr void operator()(_Tp(& __t)[_Size], _Up(& __u)[_Size]) const
noexcept(noexcept((*this)(*__t, *__u)))
{
// TODO(cjdb): replace with `ranges::swap_ranges`.
for (size_t __i = 0; __i < _Size; ++__i) {
(*this)(__t[__i], __u[__i]);
}
}
// 2.3 Otherwise, if `E1` and `E2` are lvalues of the same type `T` that models...
template<__exchangeable _Tp>
constexpr void operator()(_Tp& __x, _Tp& __y) const
noexcept(is_nothrow_move_constructible_v<_Tp> && is_nothrow_move_assignable_v<_Tp>)
{
__y = _VSTD::exchange(__x, _VSTD::move(__y));
}
};
} // namespace ranges::__swap
namespace ranges::inline __cpo {
inline constexpr auto swap = __swap::__fn{};
} // namespace ranges::__cpo
template<class _Tp>
concept swappable = requires(_Tp& __a, _Tp& __b) { ranges::swap(__a, __b); };
template<class _Tp, class _Up>
concept swappable_with =
common_reference_with<_Tp, _Up> &&
requires(_Tp&& __t, _Up&& __u) {
ranges::swap(_VSTD::forward<_Tp>(__t), _VSTD::forward<_Tp>(__t));
ranges::swap(_VSTD::forward<_Up>(__u), _VSTD::forward<_Up>(__u));
ranges::swap(_VSTD::forward<_Tp>(__t), _VSTD::forward<_Up>(__u));
ranges::swap(_VSTD::forward<_Up>(__u), _VSTD::forward<_Tp>(__t));
};
// [concept.booleantestable]
template<class _Tp>
concept __boolean_testable_impl = convertible_to<_Tp, bool>;
template<class _Tp>
concept __boolean_testable = __boolean_testable_impl<_Tp> && requires(_Tp&& __t) {
{ !std::forward<_Tp>(__t) } -> __boolean_testable_impl;
};
// [concept.equalitycomparable]
template<class _Tp, class _Up>
concept __weakly_equality_comparable_with =
requires(__make_const_lvalue_ref<_Tp> __t, __make_const_lvalue_ref<_Up> __u) {
{ __t == __u } -> __boolean_testable;
{ __t != __u } -> __boolean_testable;
{ __u == __t } -> __boolean_testable;
{ __u != __t } -> __boolean_testable;
};
template<class _Tp>
concept equality_comparable = __weakly_equality_comparable_with<_Tp, _Tp>;
template<class _Tp, class _Up>
concept equality_comparable_with =
equality_comparable<_Tp> && equality_comparable<_Up> &&
common_reference_with<__make_const_lvalue_ref<_Tp>, __make_const_lvalue_ref<_Up>> &&
equality_comparable<
common_reference_t<
__make_const_lvalue_ref<_Tp>,
__make_const_lvalue_ref<_Up>>> &&
__weakly_equality_comparable_with<_Tp, _Up>;
// [concept.totallyordered]
template<class _Tp, class _Up>
concept __partially_ordered_with =
requires(__make_const_lvalue_ref<_Tp> __t, __make_const_lvalue_ref<_Up> __u) {
{ __t < __u } -> __boolean_testable;
{ __t > __u } -> __boolean_testable;
{ __t <= __u } -> __boolean_testable;
{ __t >= __u } -> __boolean_testable;
{ __u < __t } -> __boolean_testable;
{ __u > __t } -> __boolean_testable;
{ __u <= __t } -> __boolean_testable;
{ __u >= __t } -> __boolean_testable;
};
template<class _Tp>
concept totally_ordered = equality_comparable<_Tp> && __partially_ordered_with<_Tp, _Tp>;
template<class _Tp, class _Up>
concept totally_ordered_with =
totally_ordered<_Tp> && totally_ordered<_Up> &&
equality_comparable_with<_Tp, _Up> &&
totally_ordered<
common_reference_t<
__make_const_lvalue_ref<_Tp>,
__make_const_lvalue_ref<_Up>>> &&
__partially_ordered_with<_Tp, _Up>;
// [concepts.object]
template<class _Tp>
concept movable =
is_object_v<_Tp> &&
move_constructible<_Tp> &&
assignable_from<_Tp&, _Tp> &&
swappable<_Tp>;
template<class _Tp>
concept copyable =
copy_constructible<_Tp> &&
movable<_Tp> &&
assignable_from<_Tp&, _Tp&> &&
assignable_from<_Tp&, const _Tp&> &&
assignable_from<_Tp&, const _Tp>;
template<class _Tp>
concept semiregular = copyable<_Tp> && default_initializable<_Tp>;
template<class _Tp>
concept regular = semiregular<_Tp> && equality_comparable<_Tp>;
// [concept.invocable]
template<class _Fn, class... _Args>
concept invocable = requires(_Fn&& __fn, _Args&&... __args) {
_VSTD::invoke(_VSTD::forward<_Fn>(__fn), _VSTD::forward<_Args>(__args)...); // not required to be equality preserving
};
// [concept.regular.invocable]
template<class _Fn, class... _Args>
concept regular_invocable = invocable<_Fn, _Args...>;
// [concept.predicate]
template<class _Fn, class... _Args>
concept predicate =
regular_invocable<_Fn, _Args...> && __boolean_testable<invoke_result_t<_Fn, _Args...>>;
// [concept.relation]
template<class _Rp, class _Tp, class _Up>
concept relation =
predicate<_Rp, _Tp, _Tp> && predicate<_Rp, _Up, _Up> &&
predicate<_Rp, _Tp, _Up> && predicate<_Rp, _Up, _Tp>;
// [concept.equiv]
template<class _Rp, class _Tp, class _Up>
concept equivalence_relation = relation<_Rp, _Tp, _Up>;
// [concept.strictweakorder]
template<class _Rp, class _Tp, class _Up>
concept strict_weak_order = relation<_Rp, _Tp, _Up>;
#endif // _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_CONCEPTS)
_LIBCPP_END_NAMESPACE_STD
_LIBCPP_POP_MACROS
#endif // _LIBCPP_CONCEPTS