On Thu, 30 Nov 2023 at 19:23, Patrick Palka wrote:
>
> Tested on x86_64-pc-linux-gnu, does this look OK for trunk?
OK, thanks for simplifying it.
>
> -- >8 --
>
> Use the existing _Partial range adaptor closure object in the
> definition of ranges::to instead of essentially open coding it.
>
> libstdc++-v3/ChangeLog:
>
> * include/std/ranges (__detail::_ToClosure): Replace with ...
> (__detail::_To): ... this.
> (__detail::_ToClosure2): Replace with ...
> (__detail::To2): ... this.
> (to): Simplify using the existing _Partial range adaptor
> closure object.
> ---
> libstdc++-v3/include/std/ranges | 140 ++++++++------------------------
> 1 file changed, 32 insertions(+), 108 deletions(-)
>
> diff --git a/libstdc++-v3/include/std/ranges b/libstdc++-v3/include/std/ranges
> index 9d4c2e01c4d..33e576e563a 100644
> --- a/libstdc++-v3/include/std/ranges
> +++ b/libstdc++-v3/include/std/ranges
> @@ -1007,6 +1007,7 @@ namespace views::__adaptor
>
> // Invoke _Adaptor with arguments __r, _M_args... according to the
> // value category of this _Partial object.
> + // TODO: use explicit object functions ("deducing this").
> template<typename _Range>
> requires __adaptor_invocable<_Adaptor, _Range, const _Args&...>
> constexpr auto
> @@ -1137,6 +1138,7 @@ namespace views::__adaptor
>
> // Invoke _M_rhs(_M_lhs(__r)) according to the value category of this
> // range adaptor closure object.
> + // TODO: use explicit object functions ("deducing this").
> template<typename _Range>
> requires __pipe_invocable<const _Lhs&, const _Rhs&, _Range>
> constexpr auto
> @@ -9391,59 +9393,16 @@ namespace __detail
> /// @cond undocumented
> namespace __detail
> {
> - template<typename _Cont, typename... _Args>
> - class _ToClosure
> - : public views::__adaptor::_RangeAdaptorClosure<_ToClosure<_Cont,
> _Args...>>
> + template<typename _Cont>
> + struct _To
> {
> - tuple<decay_t<_Args>...> _M_bound_args;
> -
> - public:
> - constexpr
> - _ToClosure(_Args&&... __args)
> - : _M_bound_args(std::forward<_Args>(__args)...)
> - { }
> -
> - // TODO: use explicit object functions ("deducing this").
> -
> - template<typename _Rg>
> - constexpr auto
> - operator()(_Rg&& __r) &
> - {
> - return std::apply([&__r]<typename... _Tp>(_Tp&&... __args) {
> - return ranges::to<_Cont>(std::forward<_Rg>(__r),
> - std::forward<_Tp>(__args)...);
> - }, _M_bound_args);
> - }
> -
> - template<typename _Rg>
> - constexpr auto
> - operator()(_Rg&& __r) const &
> - {
> - return std::apply([&__r]<typename... _Tp>(_Tp&&... __args) {
> - return ranges::to<_Cont>(std::forward<_Rg>(__r),
> - std::forward<_Tp>(__args)...);
> - }, _M_bound_args);
> - }
> -
> - template<typename _Rg>
> - constexpr auto
> - operator()(_Rg&& __r) &&
> - {
> - return std::apply([&__r]<typename... _Tp>(_Tp&&... __args) {
> - return ranges::to<_Cont>(std::forward<_Rg>(__r),
> - std::forward<_Tp>(__args)...);
> - }, std::move(_M_bound_args));
> - }
> -
> - template<typename _Rg>
> - constexpr auto
> - operator()(_Rg&& __r) const &&
> - {
> - return std::apply([&__r]<typename... _Tp>(_Tp&&... __args) {
> - return ranges::to<_Cont>(std::forward<_Rg>(__r),
> - std::forward<_Tp>(__args)...);
> - }, std::move(_M_bound_args));
> - }
> + template<typename _Range, typename... _Args>
> + constexpr auto
> + operator()(_Range&& __r, _Args&&... __args) const
> + {
> + return ranges::to<_Cont>(std::forward<_Range>(__r),
> + std::forward<_Args>(__args)...);
> + }
> };
> } // namespace __detail
> /// @endcond
> @@ -9465,66 +9424,27 @@ namespace __detail
> */
> template<typename _Cont, typename... _Args>
> requires (!view<_Cont>)
> - constexpr __detail::_ToClosure<_Cont, _Args...>
> + constexpr auto
> to [[nodiscard]] (_Args&&... __args)
> - { return {std::forward<_Args>(__args)...}; }
> + {
> + using __detail::_To;
> + using views::__adaptor::_Partial;
> + return _Partial<_To<_Cont>,
> decay_t<_Args>...>{std::forward<_Args>(__args)...};
> + }
>
> /// @cond undocumented
> namespace __detail
> {
> - template<template<typename...> typename _Cont, typename... _Args>
> - class _ToClosure2
> - : public views::__adaptor::_RangeAdaptorClosure<_ToClosure2<_Cont,
> _Args...>>
> + template<template<typename...> typename _Cont>
> + struct _To2
> {
> - tuple<decay_t<_Args>...> _M_bound_args;
> -
> - public:
> - constexpr
> - _ToClosure2(_Args&&... __args)
> - : _M_bound_args(std::forward<_Args>(__args)...)
> - { }
> -
> - // TODO: use explicit object functions ("deducing this").
> -
> - template<typename _Rg>
> - constexpr auto
> - operator()(_Rg&& __r) &
> - {
> - return std::apply([&__r]<typename... _Tp>(_Tp&&... __args) {
> - return ranges::to<_Cont>(std::forward<_Rg>(__r),
> - std::forward<_Tp>(__args)...);
> - }, _M_bound_args);
> - }
> -
> - template<typename _Rg>
> - constexpr auto
> - operator()(_Rg&& __r) const &
> - {
> - return std::apply([&__r]<typename... _Tp>(_Tp&&... __args) {
> - return ranges::to<_Cont>(std::forward<_Rg>(__r),
> - std::forward<_Tp>(__args)...);
> - }, _M_bound_args);
> - }
> -
> - template<typename _Rg>
> - constexpr auto
> - operator()(_Rg&& __r) &&
> - {
> - return std::apply([&__r]<typename... _Tp>(_Tp&&... __args) {
> - return ranges::to<_Cont>(std::forward<_Rg>(__r),
> - std::forward<_Tp>(__args)...);
> - }, std::move(_M_bound_args));
> - }
> -
> - template<typename _Rg>
> - constexpr auto
> - operator()(_Rg&& __r) const &&
> - {
> - return std::apply([&__r]<typename... _Tp>(_Tp&&... __args) {
> - return ranges::to<_Cont>(std::forward<_Rg>(__r),
> - std::forward<_Tp>(__args)...);
> - }, std::move(_M_bound_args));
> - }
> + template<typename _Range, typename... _Args>
> + constexpr auto
> + operator()(_Range&& __r, _Args&&... __args) const
> + {
> + return ranges::to<_Cont>(std::forward<_Range>(__r),
> + std::forward<_Args>(__args)...);
> + }
> };
> } // namespace __detail
> /// @endcond
> @@ -9547,9 +9467,13 @@ namespace __detail
> * `r | std::ranges::to<std::vector>(an_allocator)`.
> */
> template<template<typename...> typename _Cont, typename... _Args>
> - constexpr __detail::_ToClosure2<_Cont, _Args...>
> + constexpr auto
> to [[nodiscard]] (_Args&&... __args)
> - { return {std::forward<_Args>(__args)...}; }
> + {
> + using __detail::_To2;
> + using views::__adaptor::_Partial;
> + return _Partial<_To2<_Cont>,
> decay_t<_Args>...>{std::forward<_Args>(__args)...};
> + }
>
> } // namespace ranges
> #endif // __cpp_lib_ranges_to_container
> --
> 2.43.0.rc1
>
