chromium/third_party/libc++/src/include/__format/concepts.h

// -*- 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_parse_context.h>
#include <__fwd/format.h>
#include <__fwd/tuple.h>
#include <__tuple/tuple_size.h>
#include <__type_traits/is_specialization.h>
#include <__type_traits/remove_const.h>
#include <__type_traits/remove_reference.h>
#include <__utility/pair.h>

#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
#  pragma GCC system_header
#endif

_LIBCPP_BEGIN_NAMESPACE_STD

#if _LIBCPP_STD_VER >= 20

/// The character type specializations of \ref formatter.
__fmt_char_type
#  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.)
__fmt_iter_for;

__formattable_with;

__formattable;

#  if _LIBCPP_STD_VER >= 23
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> || (__is_specialization_v<_Tp, tuple> && tuple_size_v<_Tp> == 2);

#  endif // _LIBCPP_STD_VER >= 23
#endif   // _LIBCPP_STD_VER >= 20

_LIBCPP_END_NAMESPACE_STD

#endif // _LIBCPP___FORMAT_CONCEPTS_H