| // -*- C++ -*- |
| //===----------------------------------------------------------------------===// |
| // |
| // 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___FORMAT_CONCEPTS_H |
| #define _LIBCPP___FORMAT_CONCEPTS_H |
| |
| #include <__concepts/same_as.h> |
| #include <__concepts/semiregular.h> |
| #include <__config> |
| #include <__format/format_fwd.h> |
| #include <__format/format_parse_context.h> |
| #include <__type_traits/is_specialization.h> |
| #include <__utility/pair.h> |
| #include <tuple> |
| #include <type_traits> |
| |
| #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) |
| # pragma GCC system_header |
| #endif |
| |
| _LIBCPP_BEGIN_NAMESPACE_STD |
| |
| #if _LIBCPP_STD_VER > 17 |
| |
| /// The character type specializations of \ref formatter. |
| template <class _CharT> |
| concept __fmt_char_type = |
| same_as<_CharT, char> |
| # ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS |
| || same_as<_CharT, wchar_t> |
| # endif |
| ; |
| |
| // The output iterator isn't specified. A formatter should accept any |
| // output_iterator. This iterator is a minimal iterator to test the concept. |
| // (Note testing for (w)format_context would be a valid choice, but requires |
| // selecting the proper one depending on the type of _CharT.) |
| template <class _CharT> |
| using __fmt_iter_for = _CharT*; |
| |
| template <class _Tp, class _CharT> |
| concept __formattable = |
| (semiregular<formatter<remove_cvref_t<_Tp>, _CharT>>) && |
| requires(formatter<remove_cvref_t<_Tp>, _CharT> __f, |
| const formatter<remove_cvref_t<_Tp>, _CharT> __cf, |
| _Tp __t, |
| basic_format_context<__fmt_iter_for<_CharT>, _CharT> __fc, |
| basic_format_parse_context<_CharT> __pc) { |
| { __f.parse(__pc) } -> same_as<typename basic_format_parse_context<_CharT>::iterator>; |
| { __cf.format(__t, __fc) } -> same_as<__fmt_iter_for<_CharT>>; |
| }; |
| |
| # if _LIBCPP_STD_VER > 20 |
| template <class _Tp, class _CharT> |
| concept formattable = __formattable<_Tp, _CharT>; |
| |
| // [tuple.like] defines a tuple-like exposition only concept. This concept is |
| // not related to that. Therefore it uses a different name for the concept. |
| // |
| // TODO FMT Add a test to validate we fail when using that concept after P2165 |
| // has been implemented. |
| template <class _Tp> |
| concept __fmt_pair_like = __is_specialization_v<_Tp, pair> || |
| // Use a requires since tuple_size_v may fail to instantiate, |
| (__is_specialization_v<_Tp, tuple> && requires { tuple_size_v<_Tp> == 2; }); |
| |
| # endif //_LIBCPP_STD_VER > 20 |
| #endif //_LIBCPP_STD_VER > 17 |
| |
| _LIBCPP_END_NAMESPACE_STD |
| |
| #endif // _LIBCPP___FORMAT_CONCEPTS_H |