On Fri, Jun 6, 2025 at 1:02 PM Tomasz Kamiński <tkami...@redhat.com> wrote:
> This patch change implementation of the formatters for the calendar types,
> so they no longer delegate to operator<< for ostream in case of empty
> chrono-spec.
> Instead of that, we define the behavior of the in terms of format
> specifiers,
> that format specifiers are supplied by each formatter as argument to
> _M_parse
> Similary is formatter constructor it's __formatter_chrono from revalant
> default
> spec, so we preserve functionality of calling format on default cosntructed
> formatters.
>
> Expressing the existing functionality of the operaetor ostream, requires
> providing two additional features:
> * printing "is not a valid sth" for !ok objects,
> * printing a weekday index in the month.
>
> The formatter functionality is enabled by setting spec _M_debug
> (corresponding
> to '?') that is currently unused. This is currently supported only for
> subset of format specifiers used by the ostream operators. In future, we
> could
> make this user configurable (by adding '?' after 'L') and cover all flags.
>
> For the handling of the weekday index (for weekday_indexed, month_weekday,
> year_month_weekday), we need to introduce an new format specifier. To not
> conflict with future extension we use '%\0' (embedded null) as this
> character
> cannot be placed in valid format spec.
>
> Finally, the format strings for calendar types subsets each other, e.g.
> year_month_weekday_last ("%Y/%b/%a[last])" contains month_weekday_last,
> weekday_last, weekday, e.t.c.. We introduce a _ChronoFormats class that
> provide
> consteval accessors to format specs, internally sharing they
> representations.
>
> libstdc++-v3/ChangeLog:
>
> * include/bits/chrono_io.h (__format::_ChronoFormats): Define.
> (__formatter_chrono::__formatter_chrono())
> (__formatter_chrono::__formatter_chrono(_ChronoSpec<_CharT>)):
> Define.
> (__formatter_chrono::_M_parse): Add parameter with default spec,
> namd merge it with new values. Handle '%\0' as weekday index
> specifier.
> (__formatter_chrono::_M_a_A, __formatter_chrono::_M_b_B)
> (__formatter_chrono::_M_C_y_Y, __formatter_chrono::_M_d_e)
> (__formatter_chrono::_M_F): Support _M_debug flag.
> (__formatter_chrono::_M_wi, __formatter_chrono::_S_weekday_index):
> Define.
> (std::formatter<chrono::day, _CharT>)
> (std::formatter<chrono::month, _CharT>)
> (std::formatter<chrono::year, _CharT>)
> (std::formatter<chrono::weekday, _CharT>)
> (std::formatter<chrono::weekday_indexed, _CharT>)
> (std::formatter<chrono::weekday_last, _CharT>)
> (std::formatter<chrono::month_day, _CharT>)
> (std::formatter<chrono::month_day_last, _CharT>)
> (std::formatter<chrono::month_weekday, _CharT>)
> (std::formatter<chrono::month_weekday_last, _CharT>)
> (std::formatter<chrono::year_month, _CharT>)
> (std::formatter<chrono::year_month_day, _CharT>)
> (std::formatter<chrono::year_month_day_last, _CharT>)
> (std::formatter<chrono::year_month_weekday, _CharT>)
> (std::formatter<chrono::year_month_weekday_last, _CharT>):
> Define __defSpec, and pass it as argument to _M_prase and
> constructor of __formatter_chrono.
> ---
> libstdc++-v3/include/bits/chrono_io.h | 430 +++++++++++++++++++++++---
> 1 file changed, 381 insertions(+), 49 deletions(-)
>
> diff --git a/libstdc++-v3/include/bits/chrono_io.h
> b/libstdc++-v3/include/bits/chrono_io.h
> index c5c5e4bae53..e36cf1ffd31 100644
> --- a/libstdc++-v3/include/bits/chrono_io.h
> +++ b/libstdc++-v3/include/bits/chrono_io.h
> @@ -238,6 +238,93 @@ namespace __format
> operator|=(_ChronoParts& __x, _ChronoParts __y) noexcept
> { return __x = __x | __y; }
>
> + template<typename _CharT>
> + struct _ChronoFormats
> + {
> + using _String_view = basic_string_view<_CharT>;
> +
> + static consteval
> + _String_view
> + _S_f() noexcept
> + { return _GLIBCXX_WIDEN("%F"); }
> +
> + static consteval
> + _String_view
> + _S_ymd() noexcept
> + { return _GLIBCXX_WIDEN("%Y/%b/%d"); }
> +
> + static consteval
> + _String_view
> + _S_ym() noexcept
> + { return _S_ymd().substr(0, 5); }
> +
> + static consteval
> + _String_view
> + _S_md() noexcept
> + { return _S_ymd().substr(3); }
> +
> + static consteval
> + _String_view
> + _S_y() noexcept
> + { return _S_ymd().substr(0, 2); }
> +
> + static consteval
> + _String_view
> + _S_m() noexcept
> + { return _S_ymd().substr(3, 2); }
> +
> + static consteval
> + _String_view
> + _S_d() noexcept
> + { return _S_ymd().substr(6, 2); }
> +
> + static consteval
> + _String_view
> + _S_ymwi() noexcept
> + // %\0 is extension for handling weekday index
> + { return _String_view(_GLIBCXX_WIDEN("%Y/%b/%a[%\0]"), 12); }
> +
> + static consteval
> + _String_view
> + _S_mwi() noexcept
> + { return _S_ymwi().substr(3); }
> +
> + static consteval
> + _String_view
> + _S_wi() noexcept
> + { return _S_ymwi().substr(6); }
> +
> + static consteval
> + _String_view
> + _S_w() noexcept
> + { return _S_ymwi().substr(6, 2); }
> +
> + static consteval
> + _String_view
> + _S_ymwl() noexcept
> + { return _GLIBCXX_WIDEN("%Y/%b/%a[last]"); }
> +
> + static consteval
> + _String_view
> + _S_mwl() noexcept
> + { return _S_ymwl().substr(3); }
> +
> + static consteval
> + _String_view
> + _S_wl() noexcept
> + { return _S_ymwl().substr(6); }
> +
> + static consteval
> + _String_view
> + _S_yml() noexcept
> + { return _GLIBCXX_WIDEN("%Y/%b/last"); }
> +
> + static consteval
> + _String_view
> + _S_ml() noexcept
> + { return _S_yml().substr(3); }
> + };
> +
> // TODO rename this to chrono::__formatter? or
> chrono::__detail::__formatter?
> template<typename _CharT>
> struct __formatter_chrono
> @@ -245,49 +332,69 @@ namespace __format
> using __string_view = basic_string_view<_CharT>;
> using __string = basic_string<_CharT>;
>
> + __formatter_chrono() = default;
> +
> + constexpr explicit
> + __formatter_chrono(_ChronoSpec<_CharT> __spec) noexcept
> + : _M_spec(__spec)
> + { }
> +
> template<typename _ParseContext>
> constexpr typename _ParseContext::iterator
> - _M_parse(_ParseContext& __pc, _ChronoParts __parts)
> + _M_parse(_ParseContext& __pc, _ChronoParts __parts,
> + const _ChronoSpec<_CharT>& __def = {})
> {
> auto __first = __pc.begin();
> auto __last = __pc.end();
>
> _ChronoSpec<_CharT> __spec{};
>
This part could also be implemented as, let me know which version do you
prefer:
using __string_view = basic_string_view<_CharT>;
using __string = basic_string<_CharT>;
+ __formatter_chrono() = default;
+
+ constexpr explicit
+ __formatter_chrono(_ChronoSpec<_CharT> __spec) noexcept
+ : _M_spec(__spec)
+ { }
+
template<typename _ParseContext>
constexpr typename _ParseContext::iterator
- _M_parse(_ParseContext& __pc, _ChronoParts __parts)
+ _M_parse(_ParseContext& __pc, _ChronoParts __parts,
+ const _ChronoSpec<_CharT>& __def = {})
{
auto __first = __pc.begin();
auto __last = __pc.end();
- _ChronoSpec<_CharT> __spec{};
+ _ChronoSpec<_CharT> __spec = __def;
auto __finalize = [this, &__spec] {
_M_spec = __spec;
@@ -285,6 +380,7 @@ namespace __format
return __first;
}
+ __spec._M_localized = false;
__first = __spec._M_parse_locale(__first, __last);
if (__finished())
return __first;
@@ -307,6 +403,7 @@ namespace __format
// against __parts (so fail for %Y if no year in parts).
// Save range in __spec._M_chrono_specs.
+ __spec._M_debug = false;
const auto __chrono_specs = __first++; // Skip leading '%'
if (*__chrono_specs != '%')
__throw_format_error("chrono format error: no '%' at
>
> - auto __finalize = [this, &__spec] {
> - _M_spec = __spec;
> + auto __apply_default = [&] {
> + _M_spec = __def;
> + if (__spec._M_align != _Align_default)
> + {
> + _M_spec._M_align = __spec._M_align;
> + _M_spec._M_fill = __spec._M_fill;
> + }
> + if (__spec._M_width_kind != _WP_none)
> + {
> + _M_spec._M_width_kind = __spec._M_width_kind;
> + _M_spec._M_width = __spec._M_width;
> + }
> + if (__spec._M_prec_kind != _WP_none)
> + {
> + _M_spec._M_prec_kind = __spec._M_prec_kind;
> + _M_spec._M_prec = __spec._M_prec;
> + }
> + _M_spec._M_localized |= __spec._M_localized;
> + return __first;
> };
>
> auto __finished = [&] {
> - if (__first == __last || *__first == '}')
> - {
> - __finalize();
> - return true;
> - }
> - return false;
> + return __first == __last || *__first == '}';
> };
>
> if (__finished())
> - return __first;
> + return __apply_default();
>
> __first = __spec._M_parse_fill_and_align(__first, __last);
> if (__finished())
> - return __first;
> + return __apply_default();
>
> __first = __spec._M_parse_width(__first, __last, __pc);
> if (__finished())
> - return __first;
> + return __apply_default();
>
> if (__parts & _ChronoParts::_Duration)
> {
> __first = __spec._M_parse_precision(__first, __last, __pc);
> if (__finished())
> - return __first;
> + return __apply_default();
> }
>
> __first = __spec._M_parse_locale(__first, __last);
> if (__finished())
> - return __first;
> + return __apply_default();
>
> // Everything up to the end of the string or the first '}' is a
> // chrono-specs string. Check it is valid.
> @@ -562,6 +669,10 @@ namespace __format
> _CharT __c = *__first++;
> switch (__c)
> {
> + // %\0 is extension for handling weekday index
> + case '\0':
> + __out = _M_wi(__t, std::move(__out), __fc);
> + break;
> case 'a':
> case 'A':
> __out = _M_a_A(__t, std::move(__out), __fc, __c == 'A');
> @@ -816,6 +927,22 @@ namespace __format
> return __format::__write(std::move(__out), __s);
> }
>
> + template<typename _Tp, typename _FormatContext>
> + typename _FormatContext::iterator
> + _M_wi(const _Tp& __t, typename _FormatContext::iterator __out,
> + _FormatContext& __ctx) const
> + {
> + // %\0 Extension to format weekday index, used only by empty
> format spec
> + unsigned __wi = _S_weekday_index(__t);
> +
> + _CharT __buf[3];
> + __out = __format::__write(std::move(__out), _S_str_d1(__buf,
> __wi));
> + if (_M_spec._M_debug && (__wi < 1 || __wi > 5))
> + __out = __format::__write(std::move(__out),
> + __string_view(_GLIBCXX_WIDEN(" is not a valid
> index")));
> + return std::move(__out);
> + }
> +
> template<typename _Tp, typename _FormatContext>
> typename _FormatContext::iterator
> _M_a_A(const _Tp& __t, typename _FormatContext::iterator __out,
> @@ -825,7 +952,16 @@ namespace __format
> // %A Locale's full weekday name.
> chrono::weekday __wd = _S_weekday(__t);
> if (!__wd.ok())
> - __throw_format_error("format error: invalid weekday");
> + {
> + if (!_M_spec._M_debug)
> + __throw_format_error("format error: invalid weekday");
> +
> + _CharT __buf[3];
> + __out = __format::__write(std::move(__out),
> + _S_str_d1(__buf,
> __wd.c_encoding()));
> + return __format::__write(std::move(__out),
> + __string_view(_GLIBCXX_WIDEN(" is not a valid
> weekday")));
> + }
>
> locale __loc = _M_locale(__ctx);
> const auto& __tp = use_facet<__timepunct<_CharT>>(__loc);
> @@ -847,7 +983,17 @@ namespace __format
> // %B Locale's full month name.
> chrono::month __m = _S_month(__t);
> if (!__m.ok())
> - __throw_format_error("format error: invalid month");
> + {
> + if (!_M_spec._M_debug)
> + __throw_format_error("format error: invalid month");
> +
> + _CharT __buf[3];
> + __out = __format::__write(std::move(__out),
> + _S_str_d1(__buf, (unsigned)__m));
> + return __format::__write(std::move(__out),
> + __string_view(_GLIBCXX_WIDEN(" is not a valid
> month")));
> + }
> +
> locale __loc = _M_locale(__ctx);
> const auto& __tp = use_facet<__timepunct<_CharT>>(__loc);
> const _CharT* __months[12];
> @@ -974,7 +1120,11 @@ namespace __format
> }
> __out = __format::__write(std::move(__out), __sv);
> }
> - return std::move(__out);
> +
> + if (_M_spec._M_debug && __conv == 'Y' && !__y.ok()) [[unlikely]]
> + __out = __format::__write(std::move(__out),
> + __string_view(_GLIBCXX_WIDEN(" is not a valid
> year")));
> + return __out;
> }
>
> template<typename _Tp, typename _FormatContext>
> @@ -1039,7 +1189,12 @@ namespace __format
> __buf[0] = _S_space;
> __sv = {__buf, 2};
> }
> - return __format::__write(std::move(__out), __sv);
> +
> + __out = __format::__write(std::move(__out), __sv);
> + if (_M_spec._M_debug && !__d.ok()) [[unlikely]]
> + __out = __format::__write(std::move(__out),
> + __string_view(_GLIBCXX_WIDEN(" is not a valid
> day")));
> + return std::move(__out);
> }
>
> template<typename _Tp, typename _FormatContext>
> @@ -1076,6 +1231,10 @@ namespace __format
> _S_fill_two_digits(__buf + 9, __di);
> __out = __format::__write(std::move(__out), __sv);
> }
> +
> + if (_M_spec._M_debug && !__ymd.ok())
> + __out = __format::__write(std::move(__out),
> + __string_view(_GLIBCXX_WIDEN(" is not a valid
> date")));
> return std::move(__out);
> }
>
> @@ -1757,6 +1916,20 @@ namespace __format
> return weekday(_S_days(__t));
> }
>
> + template<typename _Tp>
> + static unsigned
> + _S_weekday_index(const _Tp& __t)
> + {
> + using namespace ::std::chrono;
> +
> + if constexpr (is_same_v<_Tp, weekday_indexed>)
> + return __t.index();
> + else if constexpr (requires { __t.weekday_indexed(); })
> + return __t.weekday_indexed().index();
> + else
> + return ((unsigned)_S_day(__t) + 6) / 7;
> + }
> +
> // Remove subsecond precision from a time_point.
> template<typename _Tp>
> static auto
> @@ -1851,7 +2024,7 @@ namespace __format
> {
> constexpr typename basic_format_parse_context<_CharT>::iterator
> parse(basic_format_parse_context<_CharT>& __pc)
> - { return _M_f._M_parse(__pc, __format::_Day); }
> + { return _M_f._M_parse(__pc, __format::_Day, __defSpec); }
>
> template<typename _Out>
> typename basic_format_context<_Out, _CharT>::iterator
> @@ -1860,7 +2033,15 @@ namespace __format
> { return _M_f._M_format(__t, __fc); }
>
> private:
> - __format::__formatter_chrono<_CharT> _M_f;
> + static constexpr __format::_ChronoSpec<_CharT> __defSpec = []
> + {
> + __format::_ChronoSpec<_CharT> __res{};
> + __res._M_debug = true;
> + __res._M_chrono_specs = __format::_ChronoFormats<_CharT>::_S_d();
> + return __res;
> + }();
> +
> + __format::__formatter_chrono<_CharT> _M_f{__defSpec};
> };
>
> template<__format::__char _CharT>
> @@ -1868,7 +2049,7 @@ namespace __format
> {
> constexpr typename basic_format_parse_context<_CharT>::iterator
> parse(basic_format_parse_context<_CharT>& __pc)
> - { return _M_f._M_parse(__pc, __format::_Month); }
> + { return _M_f._M_parse(__pc, __format::_Month, __defSpec); }
>
> template<typename _Out>
> typename basic_format_context<_Out, _CharT>::iterator
> @@ -1877,7 +2058,17 @@ namespace __format
> { return _M_f._M_format(__t, __fc); }
>
> private:
> - __format::__formatter_chrono<_CharT> _M_f;
> + static constexpr __format::_ChronoSpec<_CharT> __defSpec = []
> + {
> + __format::_ChronoSpec<_CharT> __res{};
> + __res._M_debug = true;
> + __res._M_localized = true;
> + __res._M_locale_specific = true;
> + __res._M_chrono_specs = __format::_ChronoFormats<_CharT>::_S_m();
> + return __res;
> + }();
> +
> + __format::__formatter_chrono<_CharT> _M_f{__defSpec};
> };
>
> template<__format::__char _CharT>
> @@ -1885,7 +2076,7 @@ namespace __format
> {
> constexpr typename basic_format_parse_context<_CharT>::iterator
> parse(basic_format_parse_context<_CharT>& __pc)
> - { return _M_f._M_parse(__pc, __format::_Year); }
> + { return _M_f._M_parse(__pc, __format::_Year, __defSpec); }
>
> template<typename _Out>
> typename basic_format_context<_Out, _CharT>::iterator
> @@ -1894,7 +2085,15 @@ namespace __format
> { return _M_f._M_format(__t, __fc); }
>
> private:
> - __format::__formatter_chrono<_CharT> _M_f;
> + static constexpr __format::_ChronoSpec<_CharT> __defSpec = []
> + {
> + __format::_ChronoSpec<_CharT> __res{};
> + __res._M_debug = true;
> + __res._M_chrono_specs = __format::_ChronoFormats<_CharT>::_S_y();
> + return __res;
> + }();
> +
> + __format::__formatter_chrono<_CharT> _M_f{__defSpec};
> };
>
> template<__format::__char _CharT>
> @@ -1902,7 +2101,7 @@ namespace __format
> {
> constexpr typename basic_format_parse_context<_CharT>::iterator
> parse(basic_format_parse_context<_CharT>& __pc)
> - { return _M_f._M_parse(__pc, __format::_Weekday); }
> + { return _M_f._M_parse(__pc, __format::_Weekday, __defSpec); }
>
> template<typename _Out>
> typename basic_format_context<_Out, _CharT>::iterator
> @@ -1911,7 +2110,17 @@ namespace __format
> { return _M_f._M_format(__t, __fc); }
>
> private:
> - __format::__formatter_chrono<_CharT> _M_f;
> + static constexpr __format::_ChronoSpec<_CharT> __defSpec = []
> + {
> + __format::_ChronoSpec<_CharT> __res{};
> + __res._M_debug = true;
> + __res._M_localized = true;
> + __res._M_locale_specific = true;
> + __res._M_chrono_specs = __format::_ChronoFormats<_CharT>::_S_w();
> + return __res;
> + }();
> +
> + __format::__formatter_chrono<_CharT> _M_f{__defSpec};
> };
>
> template<__format::__char _CharT>
> @@ -1919,7 +2128,7 @@ namespace __format
> {
> constexpr typename basic_format_parse_context<_CharT>::iterator
> parse(basic_format_parse_context<_CharT>& __pc)
> - { return _M_f._M_parse(__pc, __format::_Weekday); }
> + { return _M_f._M_parse(__pc, __format::_Weekday, __defSpec); }
>
> template<typename _Out>
> typename basic_format_context<_Out, _CharT>::iterator
> @@ -1928,7 +2137,17 @@ namespace __format
> { return _M_f._M_format(__t, __fc); }
>
> private:
> - __format::__formatter_chrono<_CharT> _M_f;
> + static constexpr __format::_ChronoSpec<_CharT> __defSpec = []
> + {
> + __format::_ChronoSpec<_CharT> __res{};
> + __res._M_debug = true;
> + __res._M_localized = true;
> + __res._M_locale_specific = true;
> + __res._M_chrono_specs =
> __format::_ChronoFormats<_CharT>::_S_wi();
> + return __res;
> + }();
> +
> + __format::__formatter_chrono<_CharT> _M_f{__defSpec};
> };
>
> template<__format::__char _CharT>
> @@ -1936,7 +2155,7 @@ namespace __format
> {
> constexpr typename basic_format_parse_context<_CharT>::iterator
> parse(basic_format_parse_context<_CharT>& __pc)
> - { return _M_f._M_parse(__pc, __format::_Weekday); }
> + { return _M_f._M_parse(__pc, __format::_Weekday, __defSpec); }
>
> template<typename _Out>
> typename basic_format_context<_Out, _CharT>::iterator
> @@ -1945,7 +2164,17 @@ namespace __format
> { return _M_f._M_format(__t, __fc); }
>
> private:
> - __format::__formatter_chrono<_CharT> _M_f;
> + static constexpr __format::_ChronoSpec<_CharT> __defSpec = []
> + {
> + __format::_ChronoSpec<_CharT> __res{};
> + __res._M_debug = true;
> + __res._M_localized = true;
> + __res._M_locale_specific = true;
> + __res._M_chrono_specs =
> __format::_ChronoFormats<_CharT>::_S_wl();
> + return __res;
> + }();
> +
> + __format::__formatter_chrono<_CharT> _M_f{__defSpec};
> };
>
> template<__format::__char _CharT>
> @@ -1953,7 +2182,10 @@ namespace __format
> {
> constexpr typename basic_format_parse_context<_CharT>::iterator
> parse(basic_format_parse_context<_CharT>& __pc)
> - { return _M_f._M_parse(__pc, __format::_Month|__format::_Day); }
> + {
> + return _M_f._M_parse(__pc, __format::_Month|__format::_Day,
> + __defSpec);
> + }
>
> template<typename _Out>
> typename basic_format_context<_Out, _CharT>::iterator
> @@ -1962,7 +2194,17 @@ namespace __format
> { return _M_f._M_format(__t, __fc); }
>
> private:
> - __format::__formatter_chrono<_CharT> _M_f;
> + static constexpr __format::_ChronoSpec<_CharT> __defSpec = []
> + {
> + __format::_ChronoSpec<_CharT> __res{};
> + __res._M_debug = true;
> + __res._M_localized = true;
> + __res._M_locale_specific = true;
> + __res._M_chrono_specs =
> __format::_ChronoFormats<_CharT>::_S_md();
> + return __res;
> + }();
> +
> + __format::__formatter_chrono<_CharT> _M_f{__defSpec};
> };
>
> template<__format::__char _CharT>
> @@ -1970,7 +2212,10 @@ namespace __format
> {
> constexpr typename basic_format_parse_context<_CharT>::iterator
> parse(basic_format_parse_context<_CharT>& __pc)
> - { return _M_f._M_parse(__pc, __format::_Month|__format::_Day); }
> + {
> + return _M_f._M_parse(__pc, __format::_Month|__format::_Day,
> + __defSpec);
> + }
>
> template<typename _Out>
> typename basic_format_context<_Out, _CharT>::iterator
> @@ -1979,7 +2224,17 @@ namespace __format
> { return _M_f._M_format(__t, __fc); }
>
> private:
> - __format::__formatter_chrono<_CharT> _M_f;
> + static constexpr __format::_ChronoSpec<_CharT> __defSpec = []
> + {
> + __format::_ChronoSpec<_CharT> __res{};
> + __res._M_debug = true;
> + __res._M_localized = true;
> + __res._M_locale_specific = true;
> + __res._M_chrono_specs =
> __format::_ChronoFormats<_CharT>::_S_ml();
> + return __res;
> + }();
> +
> + __format::__formatter_chrono<_CharT> _M_f{__defSpec};
> };
>
> template<__format::__char _CharT>
> @@ -1987,7 +2242,10 @@ namespace __format
> {
> constexpr typename basic_format_parse_context<_CharT>::iterator
> parse(basic_format_parse_context<_CharT>& __pc)
> - { return _M_f._M_parse(__pc, __format::_Month|__format::_Weekday); }
> + {
> + return _M_f._M_parse(__pc, __format::_Month|__format::_Weekday,
> + __defSpec);
> + }
>
> template<typename _Out>
> typename basic_format_context<_Out, _CharT>::iterator
> @@ -1996,7 +2254,17 @@ namespace __format
> { return _M_f._M_format(__t, __fc); }
>
> private:
> - __format::__formatter_chrono<_CharT> _M_f;
> + static constexpr __format::_ChronoSpec<_CharT> __defSpec = []
> + {
> + __format::_ChronoSpec<_CharT> __res{};
> + __res._M_debug = true;
> + __res._M_localized = true;
> + __res._M_locale_specific = true;
> + __res._M_chrono_specs =
> __format::_ChronoFormats<_CharT>::_S_mwi();
> + return __res;
> + }();
> +
> + __format::__formatter_chrono<_CharT> _M_f{__defSpec};
> };
>
> template<__format::__char _CharT>
> @@ -2004,7 +2272,10 @@ namespace __format
> {
> constexpr typename basic_format_parse_context<_CharT>::iterator
> parse(basic_format_parse_context<_CharT>& __pc)
> - { return _M_f._M_parse(__pc, __format::_Month|__format::_Weekday); }
> + {
> + return _M_f._M_parse(__pc, __format::_Month|__format::_Weekday,
> + __defSpec);
> + }
>
> template<typename _Out>
> typename basic_format_context<_Out, _CharT>::iterator
> @@ -2013,7 +2284,17 @@ namespace __format
> { return _M_f._M_format(__t, __fc); }
>
> private:
> - __format::__formatter_chrono<_CharT> _M_f;
> + static constexpr __format::_ChronoSpec<_CharT> __defSpec = []
> + {
> + __format::_ChronoSpec<_CharT> __res{};
> + __res._M_debug = true;
> + __res._M_localized = true;
> + __res._M_locale_specific = true;
> + __res._M_chrono_specs =
> __format::_ChronoFormats<_CharT>::_S_mwl();
> + return __res;
> + }();
> +
> + __format::__formatter_chrono<_CharT> _M_f{__defSpec};
> };
>
> template<__format::__char _CharT>
> @@ -2021,7 +2302,10 @@ namespace __format
> {
> constexpr typename basic_format_parse_context<_CharT>::iterator
> parse(basic_format_parse_context<_CharT>& __pc)
> - { return _M_f._M_parse(__pc, __format::_Year|__format::_Month); }
> + {
> + return _M_f._M_parse(__pc, __format::_Year|__format::_Month,
> + __defSpec);
> + }
>
> template<typename _Out>
> typename basic_format_context<_Out, _CharT>::iterator
> @@ -2030,7 +2314,17 @@ namespace __format
> { return _M_f._M_format(__t, __fc); }
>
> private:
> - __format::__formatter_chrono<_CharT> _M_f;
> + static constexpr __format::_ChronoSpec<_CharT> __defSpec = []
> + {
> + __format::_ChronoSpec<_CharT> __res{};
> + __res._M_debug = true;
> + __res._M_localized = true;
> + __res._M_locale_specific = true;
> + __res._M_chrono_specs =
> __format::_ChronoFormats<_CharT>::_S_ym();
> + return __res;
> + }();
> +
> + __format::__formatter_chrono<_CharT> _M_f{__defSpec};
> };
>
> template<__format::__char _CharT>
> @@ -2038,7 +2332,7 @@ namespace __format
> {
> constexpr typename basic_format_parse_context<_CharT>::iterator
> parse(basic_format_parse_context<_CharT>& __pc)
> - { return _M_f._M_parse(__pc, __format::_Date); }
> + { return _M_f._M_parse(__pc, __format::_Date, __defSpec); }
>
> template<typename _Out>
> typename basic_format_context<_Out, _CharT>::iterator
> @@ -2047,7 +2341,15 @@ namespace __format
> { return _M_f._M_format(__t, __fc); }
>
> private:
> - __format::__formatter_chrono<_CharT> _M_f;
> + static constexpr __format::_ChronoSpec<_CharT> __defSpec = []
> + {
> + __format::_ChronoSpec<_CharT> __res{};
> + __res._M_debug = true;
> + __res._M_chrono_specs = __format::_ChronoFormats<_CharT>::_S_f();
> + return __res;
> + }();
> +
> + __format::__formatter_chrono<_CharT> _M_f{__defSpec};
> };
>
> template<__format::__char _CharT>
> @@ -2055,7 +2357,7 @@ namespace __format
> {
> constexpr typename basic_format_parse_context<_CharT>::iterator
> parse(basic_format_parse_context<_CharT>& __pc)
> - { return _M_f._M_parse(__pc, __format::_Date); }
> + { return _M_f._M_parse(__pc, __format::_Date, __defSpec); }
>
> template<typename _Out>
> typename basic_format_context<_Out, _CharT>::iterator
> @@ -2064,7 +2366,17 @@ namespace __format
> { return _M_f._M_format(__t, __fc); }
>
> private:
> - __format::__formatter_chrono<_CharT> _M_f;
> + static constexpr __format::_ChronoSpec<_CharT> __defSpec = []
> + {
> + __format::_ChronoSpec<_CharT> __res{};
> + __res._M_debug = true;
> + __res._M_localized = true;
> + __res._M_locale_specific = true;
> + __res._M_chrono_specs =
> __format::_ChronoFormats<_CharT>::_S_yml();
> + return __res;
> + }();
> +
> + __format::__formatter_chrono<_CharT> _M_f{__defSpec};
> };
>
> template<__format::__char _CharT>
> @@ -2072,7 +2384,7 @@ namespace __format
> {
> constexpr typename basic_format_parse_context<_CharT>::iterator
> parse(basic_format_parse_context<_CharT>& __pc)
> - { return _M_f._M_parse(__pc, __format::_Date); }
> + { return _M_f._M_parse(__pc, __format::_Date, __defSpec); }
>
> template<typename _Out>
> typename basic_format_context<_Out, _CharT>::iterator
> @@ -2081,7 +2393,17 @@ namespace __format
> { return _M_f._M_format(__t, __fc); }
>
> private:
> - __format::__formatter_chrono<_CharT> _M_f;
> + static constexpr __format::_ChronoSpec<_CharT> __defSpec = []
> + {
> + __format::_ChronoSpec<_CharT> __res{};
> + __res._M_debug = true;
> + __res._M_localized = true;
> + __res._M_locale_specific = true;
> + __res._M_chrono_specs =
> __format::_ChronoFormats<_CharT>::_S_ymwi();
> + return __res;
> + }();
> +
> + __format::__formatter_chrono<_CharT> _M_f{__defSpec};
> };
>
> template<__format::__char _CharT>
> @@ -2089,7 +2411,7 @@ namespace __format
> {
> constexpr typename basic_format_parse_context<_CharT>::iterator
> parse(basic_format_parse_context<_CharT>& __pc)
> - { return _M_f._M_parse(__pc, __format::_Date); }
> + { return _M_f._M_parse(__pc, __format::_Date, __defSpec); }
>
> template<typename _Out>
> typename basic_format_context<_Out, _CharT>::iterator
> @@ -2098,7 +2420,17 @@ namespace __format
> { return _M_f._M_format(__t, __fc); }
>
> private:
> - __format::__formatter_chrono<_CharT> _M_f;
> + static constexpr __format::_ChronoSpec<_CharT> __defSpec = []
> + {
> + __format::_ChronoSpec<_CharT> __res{};
> + __res._M_debug = true;
> + __res._M_localized = true;
> + __res._M_locale_specific = true;
> + __res._M_chrono_specs =
> __format::_ChronoFormats<_CharT>::_S_ymwl();
> + return __res;
> + }();
> +
> + __format::__formatter_chrono<_CharT> _M_f{__defSpec};
> };
>
> template<typename _Rep, typename _Period, __format::__char _CharT>
> @@ -2947,7 +3279,7 @@ namespace __detail
> // n.b. only decimal separator is locale dependent for specifiers
> // used below, as sys_info uses seconds and minutes duration, the
> // output is locale-independent.
> - constexpr auto* __fs
> + constexpr auto* __fs
> = _GLIBCXX_WIDEN("[{0:%F %T},{1:%F %T},{2:%T},{3:%Q%q},{0:%Z}]");
> local_seconds __lb(__i.begin.time_since_epoch());
> __os << std::format(__fs, local_time_format(__lb, &__i.abbrev),
> --
> 2.49.0
>
>
