1*81ad6265SDimitry Andric // -*- C++ -*- 2*81ad6265SDimitry Andric //===----------------------------------------------------------------------===// 3*81ad6265SDimitry Andric // 4*81ad6265SDimitry Andric // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 5*81ad6265SDimitry Andric // See https://llvm.org/LICENSE.txt for license information. 6*81ad6265SDimitry Andric // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 7*81ad6265SDimitry Andric // 8*81ad6265SDimitry Andric //===----------------------------------------------------------------------===// 9*81ad6265SDimitry Andric 10*81ad6265SDimitry Andric #ifndef _LIBCPP___FORMAT_CONCEPTS_H 11*81ad6265SDimitry Andric #define _LIBCPP___FORMAT_CONCEPTS_H 12*81ad6265SDimitry Andric 13*81ad6265SDimitry Andric #include <__concepts/same_as.h> 14*81ad6265SDimitry Andric #include <__concepts/semiregular.h> 15*81ad6265SDimitry Andric #include <__config> 16*81ad6265SDimitry Andric #include <__format/format_fwd.h> 17*81ad6265SDimitry Andric #include <__format/format_parse_context.h> 18*81ad6265SDimitry Andric #include <type_traits> 19*81ad6265SDimitry Andric 20*81ad6265SDimitry Andric #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 21*81ad6265SDimitry Andric # pragma GCC system_header 22*81ad6265SDimitry Andric #endif 23*81ad6265SDimitry Andric 24*81ad6265SDimitry Andric _LIBCPP_BEGIN_NAMESPACE_STD 25*81ad6265SDimitry Andric 26*81ad6265SDimitry Andric #if _LIBCPP_STD_VER > 17 27*81ad6265SDimitry Andric 28*81ad6265SDimitry Andric // The output iterator isn't specified. A formatter should accept any 29*81ad6265SDimitry Andric // output_iterator. This iterator is a minimal iterator to test the concept. 30*81ad6265SDimitry Andric // (Note testing for (w)format_context would be a valid choice, but requires 31*81ad6265SDimitry Andric // selecting the proper one depending on the type of _CharT.) 32*81ad6265SDimitry Andric template <class _CharT> 33*81ad6265SDimitry Andric using __fmt_iter_for = _CharT*; 34*81ad6265SDimitry Andric 35*81ad6265SDimitry Andric // The concept is based on P2286R6 36*81ad6265SDimitry Andric // It lacks the const of __cf as required by, the not yet accepted, LWG-3636. 37*81ad6265SDimitry Andric // The current formatters can't be easily adapted, but that is WIP. 38*81ad6265SDimitry Andric // TODO FMT properly implement this concepts once accepted. 39*81ad6265SDimitry Andric template <class _Tp, class _CharT> 40*81ad6265SDimitry Andric concept __formattable = (semiregular<formatter<remove_cvref_t<_Tp>, _CharT>>) && 41*81ad6265SDimitry Andric requires(formatter<remove_cvref_t<_Tp>, _CharT> __f, 42*81ad6265SDimitry Andric formatter<remove_cvref_t<_Tp>, _CharT> __cf, _Tp __t, 43*81ad6265SDimitry Andric basic_format_context<__fmt_iter_for<_CharT>, _CharT> __fc, 44*81ad6265SDimitry Andric basic_format_parse_context<_CharT> __pc) { 45*81ad6265SDimitry Andric { __f.parse(__pc) } -> same_as<typename basic_format_parse_context<_CharT>::iterator>; 46*81ad6265SDimitry Andric { __cf.format(__t, __fc) } -> same_as<__fmt_iter_for<_CharT>>; 47*81ad6265SDimitry Andric }; 48*81ad6265SDimitry Andric 49*81ad6265SDimitry Andric #endif //_LIBCPP_STD_VER > 17 50*81ad6265SDimitry Andric 51*81ad6265SDimitry Andric _LIBCPP_END_NAMESPACE_STD 52*81ad6265SDimitry Andric 53*81ad6265SDimitry Andric #endif // _LIBCPP___FORMAT_CONCEPTS_H 54