libcxx/include/__tuple/tuple_like.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___TUPLE_TUPLE_LIKE_H
  10 #define _LIBCPP___TUPLE_TUPLE_LIKE_H
  11
  12 #include <__config>
  13 #include <__fwd/subrange.h>
  14 #include <__tuple/tuple_like_no_subrange.h>
  15 #include <__tuple/tuple_size.h>
  16 #include <__type_traits/remove_cvref.h>
  17
  18 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
  19 #  pragma GCC system_header
  20 #endif
  21
  22 _LIBCPP_BEGIN_NAMESPACE_STD
  23
  24 #if _LIBCPP_STD_VER >= 20
  25
  26 template <class _Tp>
  27 inline constexpr bool __is_ranges_subrange_v = false;
  28
  29 template <class _Iter, class _Sent, ranges::subrange_kind _Kind>
  30 inline constexpr bool __is_ranges_subrange_v<ranges::subrange<_Iter, _Sent, _Kind>> = true;
  31
  32 template <class _Tp>
  33 concept __tuple_like = __tuple_like_no_subrange<_Tp> || __is_ranges_subrange_v<remove_cvref_t<_Tp>>;
  34
  35 // As of writing this comment every use of `pair-like` in the standard excludes `ranges::subrange`, so
  36 // you most likely want to use `__pair_like_no_subrange` if you're looking for `pair-like`.
  37
  38 #endif // _LIBCPP_STD_VER >= 20
  39
  40 _LIBCPP_END_NAMESPACE_STD
  41
  42 #endif // _LIBCPP___TUPLE_TUPLE_LIKE_H