diff options
Diffstat (limited to 'libcxx/include/__format/concepts.h')
| -rw-r--r-- | libcxx/include/__format/concepts.h | 49 |
1 files changed, 37 insertions, 12 deletions
diff --git a/libcxx/include/__format/concepts.h b/libcxx/include/__format/concepts.h index 8df6493b0aed..fe4a7b9625ce 100644 --- a/libcxx/include/__format/concepts.h +++ b/libcxx/include/__format/concepts.h @@ -15,6 +15,9 @@ #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) @@ -25,6 +28,15 @@ _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 @@ -32,20 +44,33 @@ _LIBCPP_BEGIN_NAMESPACE_STD template <class _CharT> using __fmt_iter_for = _CharT*; -// The concept is based on P2286R6 -// It lacks the const of __cf as required by, the not yet accepted, LWG-3636. -// The current formatters can't be easily adapted, but that is WIP. -// TODO FMT properly implement this concepts once accepted. template <class _Tp, class _CharT> -concept __formattable = (semiregular<formatter<remove_cvref_t<_Tp>, _CharT>>) && - requires(formatter<remove_cvref_t<_Tp>, _CharT> __f, - 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>>; - }; +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 |