v1/__tuple/tuple_like.h

0001 //===----------------------------------------------------------------------===//
0002 //
0003 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
0004 // See https://llvm.org/LICENSE.txt for license information.
0005 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
0006 //
0007 //===----------------------------------------------------------------------===//
0008
0009 #ifndef _LIBCPP___TUPLE_TUPLE_LIKE_H
0010 #define _LIBCPP___TUPLE_TUPLE_LIKE_H
0011
0012 #include <__config>
0013 #include <__fwd/subrange.h>
0014 #include <__tuple/tuple_like_no_subrange.h>
0015 #include <__tuple/tuple_size.h>
0016 #include <__type_traits/remove_cvref.h>
0017
0018 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
0019 #  pragma GCC system_header
0020 #endif
0021
0022 _LIBCPP_BEGIN_NAMESPACE_STD
0023
0024 #if _LIBCPP_STD_VER >= 20
0025
0026 template <class _Tp>
0027 inline constexpr bool __is_ranges_subrange_v = false;
0028
0029 template <class _Iter, class _Sent, ranges::subrange_kind _Kind>
0030 inline constexpr bool __is_ranges_subrange_v<ranges::subrange<_Iter, _Sent, _Kind>> = true;
0031
0032 template <class _Tp>
0033 concept __tuple_like = __tuple_like_no_subrange<_Tp> || __is_ranges_subrange_v<remove_cvref_t<_Tp>>;
0034
0035 // As of writing this comment every use of `pair-like` in the standard excludes `ranges::subrange`, so
0036 // you most likely want to use `__pair_like_no_subrange` if you're looking for `pair-like`.
0037
0038 #endif // _LIBCPP_STD_VER >= 20
0039
0040 _LIBCPP_END_NAMESPACE_STD
0041
0042 #endif // _LIBCPP___TUPLE_TUPLE_LIKE_H