1 // -*- C++ -*- 2 //===----------------------------------------------------------------------===// 3 // 4 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 5 // See https://llvm.org/LICENSE.txt for license information. 6 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 7 // 8 //===----------------------------------------------------------------------===// 9 10 #ifndef _LIBCPP___FORMAT_CONCEPTS_H 11 #define _LIBCPP___FORMAT_CONCEPTS_H 12 13 #include <__concepts/same_as.h> 14 #include <__concepts/semiregular.h> 15 #include <__config> 16 #include <__format/format_parse_context.h> 17 #include <__fwd/format.h> 18 #include <__fwd/tuple.h> 19 #include <__tuple/tuple_size.h> 20 #include <__type_traits/is_specialization.h> 21 #include <__type_traits/remove_const.h> 22 #include <__type_traits/remove_reference.h> 23 #include <__utility/pair.h> 24 25 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 26 # pragma GCC system_header 27 #endif 28 29 _LIBCPP_BEGIN_NAMESPACE_STD 30 31 #if _LIBCPP_STD_VER >= 20 32 33 /// The character type specializations of \ref formatter. 34 template <class _CharT> 35 concept __fmt_char_type = 36 same_as<_CharT, char> 37 # ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS 38 || same_as<_CharT, wchar_t> 39 # endif 40 ; 41 42 // The output iterator isn't specified. A formatter should accept any 43 // output_iterator. This iterator is a minimal iterator to test the concept. 44 // (Note testing for (w)format_context would be a valid choice, but requires 45 // selecting the proper one depending on the type of _CharT.) 46 template <class _CharT> 47 using __fmt_iter_for = _CharT*; 48 49 template <class _Tp, class _Context, class _Formatter = typename _Context::template formatter_type<remove_const_t<_Tp>>> 50 concept __formattable_with = 51 semiregular<_Formatter> && requires(_Formatter & __f,const _Formatter & __cf,_Tp && __t,_Context __fc,basic_format_parse_context<typename _Context::char_type> __pc)52 requires(_Formatter& __f, 53 const _Formatter& __cf, 54 _Tp&& __t, 55 _Context __fc, 56 basic_format_parse_context<typename _Context::char_type> __pc) { 57 { __f.parse(__pc) } -> same_as<typename decltype(__pc)::iterator>; 58 { __cf.format(__t, __fc) } -> same_as<typename _Context::iterator>; 59 }; 60 61 template <class _Tp, class _CharT> 62 concept __formattable = 63 __formattable_with<remove_reference_t<_Tp>, basic_format_context<__fmt_iter_for<_CharT>, _CharT>>; 64 65 # if _LIBCPP_STD_VER >= 23 66 template <class _Tp, class _CharT> 67 concept formattable = __formattable<_Tp, _CharT>; 68 69 // [tuple.like] defines a tuple-like exposition only concept. This concept is 70 // not related to that. Therefore it uses a different name for the concept. 71 // 72 // TODO FMT Add a test to validate we fail when using that concept after P2165 73 // has been implemented. 74 template <class _Tp> 75 concept __fmt_pair_like = 76 __is_specialization_v<_Tp, pair> || (__is_specialization_v<_Tp, tuple> && tuple_size_v<_Tp> == 2); 77 78 # endif //_LIBCPP_STD_VER >= 23 79 #endif //_LIBCPP_STD_VER >= 20 80 81 _LIBCPP_END_NAMESPACE_STD 82 83 #endif // _LIBCPP___FORMAT_CONCEPTS_H 84