libcxx/include/__concepts/relation.h

   1 //===----------------------------------------------------------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 #ifndef _LIBCPP___CONCEPTS_RELATION_H
  10 #define _LIBCPP___CONCEPTS_RELATION_H
  11
  12 #include <__concepts/predicate.h>
  13 #include <__config>
  14
  15 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
  16 #  pragma GCC system_header
  17 #endif
  18
  19 _LIBCPP_BEGIN_NAMESPACE_STD
  20
  21 #if _LIBCPP_STD_VER >= 20
  22
  23 // [concept.relation]
  24
  25 template <class _Rp, class _Tp, class _Up>
  26 concept relation =
  27     predicate<_Rp, _Tp, _Tp> && predicate<_Rp, _Up, _Up> && predicate<_Rp, _Tp, _Up> && predicate<_Rp, _Up, _Tp>;
  28
  29 // [concept.equiv]
  30
  31 template <class _Rp, class _Tp, class _Up>
  32 concept equivalence_relation = relation<_Rp, _Tp, _Up>;
  33
  34 // [concept.strictweakorder]
  35
  36 template <class _Rp, class _Tp, class _Up>
  37 concept strict_weak_order = relation<_Rp, _Tp, _Up>;
  38
  39 #endif // _LIBCPP_STD_VER >= 20
  40
  41 _LIBCPP_END_NAMESPACE_STD
  42
  43 #endif // _LIBCPP___CONCEPTS_RELATION_H