| Message ID | 20240111002623.2514687-1-ppalka@redhat.com |
|---|---|
| State | New |
| Headers | show |
| Series | libstdc++/ranges: Use C++23 deducing this for _Pipe and _Partial | expand |
On Thu, 11 Jan 2024 at 00:26, Patrick Palka <ppalka@redhat.com> wrote: > > Tested on x86_64-pc-linux-gnu, does this look OK for trunk? OK. Nice to see explicit object functions landing in the library so soon! > > -- >8 -- > > This simplifies the operator() of the _Pipe and _Partial range adaptor > closure objects using C++23 deducing this, allowing us to condense > multiple operator() overloads into one. > > The new __like_t alias template is similar to the expositional one from > P0847R6, except it's implemented in terms of forward_like instead of vice > versa, and thus ours always yields a reference, so e.g. __like_t<A, char> > is char&&. This shouldn't make a difference in practice, I think.. > > libstdc++-v3/ChangeLog: > > * include/bits/move.h (__like_t): Define. > * include/std/ranges (views::__adaptor::Partial::operator()): > Implement using C++23 deducing this when available. > (views::__adaptor::_Pipe::operator()): Likewise. > * testsuite/std/ranges/adaptors/100577.cc: Adjust testcase to > accept "no match for call" errors issued in C++23 mode instead > of "use of deleted function". > * testsuite/std/ranges/adaptors/lazy_split_neg.cc: Likewise. > --- > libstdc++-v3/include/bits/move.h | 3 ++ > libstdc++-v3/include/std/ranges | 37 ++++++++++++++++++- > .../testsuite/std/ranges/adaptors/100577.cc | 18 ++++----- > .../std/ranges/adaptors/lazy_split_neg.cc | 2 +- > 4 files changed, 48 insertions(+), 12 deletions(-) > > diff --git a/libstdc++-v3/include/bits/move.h b/libstdc++-v3/include/bits/move.h > index 4e741bcdeb0..bb200c95964 100644 > --- a/libstdc++-v3/include/bits/move.h > +++ b/libstdc++-v3/include/bits/move.h > @@ -110,6 +110,9 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION > return static_cast<_Up&>(__x); > } > } > + > + template<typename _Tp, typename _Up> > + using __like_t = decltype(std::forward_like<_Tp>(std::declval<_Up>())); > #endif > > /** > diff --git a/libstdc++-v3/include/std/ranges b/libstdc++-v3/include/std/ranges > index 0734daa42bf..8d2649cf5b9 100644 > --- a/libstdc++-v3/include/std/ranges > +++ b/libstdc++-v3/include/std/ranges > @@ -1016,7 +1016,19 @@ 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"). > +#if __cpp_explicit_this_parameter > + template<typename _Self, typename _Range> > + requires __adaptor_invocable<_Adaptor, _Range, __like_t<_Self, _Args>...> > + constexpr auto > + operator()(this _Self&& __self, _Range&& __r) > + { > + auto __forwarder = [&__r] (auto&&... __args) { > + return _Adaptor{}(std::forward<_Range>(__r), > + std::forward<decltype(__args)>(__args)...); > + }; > + return std::apply(__forwarder, std::forward<_Self>(__self)._M_args); > + } > +#else > template<typename _Range> > requires __adaptor_invocable<_Adaptor, _Range, const _Args&...> > constexpr auto > @@ -1042,6 +1054,7 @@ namespace views::__adaptor > template<typename _Range> > constexpr auto > operator()(_Range&& __r) const && = delete; > +#endif > }; > > // A lightweight specialization of the above primary template for > @@ -1058,6 +1071,14 @@ namespace views::__adaptor > : _M_arg(std::forward<_Tp>(__arg)) > { } > > +#if __cpp_explicit_this_parameter > + template<typename _Self, typename _Range> > + requires __adaptor_invocable<_Adaptor, _Range, __like_t<_Self, _Arg>> > + constexpr auto > + operator()(this _Self&& __self, _Range&& __r) > + { return _Adaptor{}(std::forward<_Range>(__r), > + std::forward<_Self>(__self)._M_arg); } > +#else > template<typename _Range> > requires __adaptor_invocable<_Adaptor, _Range, const _Arg&> > constexpr auto > @@ -1073,6 +1094,7 @@ namespace views::__adaptor > template<typename _Range> > constexpr auto > operator()(_Range&& __r) const && = delete; > +#endif > }; > > // Partial specialization of the primary template for the case where the extra > @@ -1154,7 +1176,17 @@ 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"). > +#if __cpp_explicit_this_parameter > + template<typename _Self, typename _Range> > + requires __pipe_invocable<__like_t<_Self, _Lhs>, __like_t<_Self, _Rhs>, _Range> > + constexpr auto > + operator()(this _Self&& __self, _Range&& __r) > + { > + return (std::forward<_Self>(__self)._M_rhs > + (std::forward<_Self>(__self)._M_lhs > + (std::forward<_Range>(__r)))); > + } > +#else > template<typename _Range> > requires __pipe_invocable<const _Lhs&, const _Rhs&, _Range> > constexpr auto > @@ -1170,6 +1202,7 @@ namespace views::__adaptor > template<typename _Range> > constexpr auto > operator()(_Range&& __r) const && = delete; > +#endif > }; > > // A partial specialization of the above primary template for the case where > diff --git a/libstdc++-v3/testsuite/std/ranges/adaptors/100577.cc b/libstdc++-v3/testsuite/std/ranges/adaptors/100577.cc > index 69072d69fec..3a52f5b4ce0 100644 > --- a/libstdc++-v3/testsuite/std/ranges/adaptors/100577.cc > +++ b/libstdc++-v3/testsuite/std/ranges/adaptors/100577.cc > @@ -98,28 +98,28 @@ test02() > (views::take_while(badarg) | views::all)(x); // { dg-error "no match" } > (views::drop_while(badarg) | views::all)(x); // { dg-error "no match" } > > - // In practice, range adaptor closures with non-simple operator() are > + // In C++20 mode, range adaptor closures with non-simple operator() are > // implemented using a fallback deleted overload, so when a call is > // ill-formed overload resolution succeeds but selects the deleted overload > // (but only when the closure is invoked as an rvalue). > - views::lazy_split(badarg)(x); // { dg-error "deleted function" } > - (views::lazy_split(badarg) | views::all)(x); // { dg-error "deleted function" } > + views::lazy_split(badarg)(x); // { dg-error "deleted function|no match" } > + (views::lazy_split(badarg) | views::all)(x); // { dg-error "deleted function|no match" } > auto a0 = views::lazy_split(badarg); > a0(x); // { dg-error "no match" }; > auto a1 = a0 | views::all; > a1(x); // { dg-error "no match" } > > - views::split(badarg)(x); // { dg-error "deleted function" } > - (views::split(badarg) | views::all)(x); // { dg-error "deleted function" } > + views::split(badarg)(x); // { dg-error "deleted function|no match" } > + (views::split(badarg) | views::all)(x); // { dg-error "deleted function|no match" } > auto a0a = views::split(badarg); > a0a(x); // { dg-error "no match" }; > auto a1a = a0a | views::all; > a1a(x); // { dg-error "no match" } > > - views::take(badarg)(x); // { dg-error "deleted" } > - views::drop(badarg)(x); // { dg-error "deleted" } > - (views::take(badarg) | views::all)(x); // { dg-error "deleted" } > - (views::drop(badarg) | views::all)(x); // { dg-error "deleted" } > + views::take(badarg)(x); // { dg-error "deleted|no match" } > + views::drop(badarg)(x); // { dg-error "deleted|no match" } > + (views::take(badarg) | views::all)(x); // { dg-error "deleted|no match" } > + (views::drop(badarg) | views::all)(x); // { dg-error "deleted|no match" } > } > > void > diff --git a/libstdc++-v3/testsuite/std/ranges/adaptors/lazy_split_neg.cc b/libstdc++-v3/testsuite/std/ranges/adaptors/lazy_split_neg.cc > index 683ea76da07..85632759fcc 100644 > --- a/libstdc++-v3/testsuite/std/ranges/adaptors/lazy_split_neg.cc > +++ b/libstdc++-v3/testsuite/std/ranges/adaptors/lazy_split_neg.cc > @@ -38,7 +38,7 @@ test02() > { > using namespace std::literals; > auto x = "the quick brown fox"sv; > - auto v1 = views::lazy_split(std::initializer_list<char>{' ', ' '})(x); // { dg-error "deleted" } > + auto v1 = views::lazy_split(std::initializer_list<char>{' ', ' '})(x); // { dg-error "deleted|no match" } > auto v2 = x | views::lazy_split(std::initializer_list<char>{' ', ' '}); // { dg-error "no match" } > } > > -- > 2.43.0.283.ga54a84b333 >
diff --git a/libstdc++-v3/include/bits/move.h b/libstdc++-v3/include/bits/move.h index 4e741bcdeb0..bb200c95964 100644 --- a/libstdc++-v3/include/bits/move.h +++ b/libstdc++-v3/include/bits/move.h @@ -110,6 +110,9 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION return static_cast<_Up&>(__x); } } + + template<typename _Tp, typename _Up> + using __like_t = decltype(std::forward_like<_Tp>(std::declval<_Up>())); #endif /** diff --git a/libstdc++-v3/include/std/ranges b/libstdc++-v3/include/std/ranges index 0734daa42bf..8d2649cf5b9 100644 --- a/libstdc++-v3/include/std/ranges +++ b/libstdc++-v3/include/std/ranges @@ -1016,7 +1016,19 @@ 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"). +#if __cpp_explicit_this_parameter + template<typename _Self, typename _Range> + requires __adaptor_invocable<_Adaptor, _Range, __like_t<_Self, _Args>...> + constexpr auto + operator()(this _Self&& __self, _Range&& __r) + { + auto __forwarder = [&__r] (auto&&... __args) { + return _Adaptor{}(std::forward<_Range>(__r), + std::forward<decltype(__args)>(__args)...); + }; + return std::apply(__forwarder, std::forward<_Self>(__self)._M_args); + } +#else template<typename _Range> requires __adaptor_invocable<_Adaptor, _Range, const _Args&...> constexpr auto @@ -1042,6 +1054,7 @@ namespace views::__adaptor template<typename _Range> constexpr auto operator()(_Range&& __r) const && = delete; +#endif }; // A lightweight specialization of the above primary template for @@ -1058,6 +1071,14 @@ namespace views::__adaptor : _M_arg(std::forward<_Tp>(__arg)) { } +#if __cpp_explicit_this_parameter + template<typename _Self, typename _Range> + requires __adaptor_invocable<_Adaptor, _Range, __like_t<_Self, _Arg>> + constexpr auto + operator()(this _Self&& __self, _Range&& __r) + { return _Adaptor{}(std::forward<_Range>(__r), + std::forward<_Self>(__self)._M_arg); } +#else template<typename _Range> requires __adaptor_invocable<_Adaptor, _Range, const _Arg&> constexpr auto @@ -1073,6 +1094,7 @@ namespace views::__adaptor template<typename _Range> constexpr auto operator()(_Range&& __r) const && = delete; +#endif }; // Partial specialization of the primary template for the case where the extra @@ -1154,7 +1176,17 @@ 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"). +#if __cpp_explicit_this_parameter + template<typename _Self, typename _Range> + requires __pipe_invocable<__like_t<_Self, _Lhs>, __like_t<_Self, _Rhs>, _Range> + constexpr auto + operator()(this _Self&& __self, _Range&& __r) + { + return (std::forward<_Self>(__self)._M_rhs + (std::forward<_Self>(__self)._M_lhs + (std::forward<_Range>(__r)))); + } +#else template<typename _Range> requires __pipe_invocable<const _Lhs&, const _Rhs&, _Range> constexpr auto @@ -1170,6 +1202,7 @@ namespace views::__adaptor template<typename _Range> constexpr auto operator()(_Range&& __r) const && = delete; +#endif }; // A partial specialization of the above primary template for the case where diff --git a/libstdc++-v3/testsuite/std/ranges/adaptors/100577.cc b/libstdc++-v3/testsuite/std/ranges/adaptors/100577.cc index 69072d69fec..3a52f5b4ce0 100644 --- a/libstdc++-v3/testsuite/std/ranges/adaptors/100577.cc +++ b/libstdc++-v3/testsuite/std/ranges/adaptors/100577.cc @@ -98,28 +98,28 @@ test02() (views::take_while(badarg) | views::all)(x); // { dg-error "no match" } (views::drop_while(badarg) | views::all)(x); // { dg-error "no match" } - // In practice, range adaptor closures with non-simple operator() are + // In C++20 mode, range adaptor closures with non-simple operator() are // implemented using a fallback deleted overload, so when a call is // ill-formed overload resolution succeeds but selects the deleted overload // (but only when the closure is invoked as an rvalue). - views::lazy_split(badarg)(x); // { dg-error "deleted function" } - (views::lazy_split(badarg) | views::all)(x); // { dg-error "deleted function" } + views::lazy_split(badarg)(x); // { dg-error "deleted function|no match" } + (views::lazy_split(badarg) | views::all)(x); // { dg-error "deleted function|no match" } auto a0 = views::lazy_split(badarg); a0(x); // { dg-error "no match" }; auto a1 = a0 | views::all; a1(x); // { dg-error "no match" } - views::split(badarg)(x); // { dg-error "deleted function" } - (views::split(badarg) | views::all)(x); // { dg-error "deleted function" } + views::split(badarg)(x); // { dg-error "deleted function|no match" } + (views::split(badarg) | views::all)(x); // { dg-error "deleted function|no match" } auto a0a = views::split(badarg); a0a(x); // { dg-error "no match" }; auto a1a = a0a | views::all; a1a(x); // { dg-error "no match" } - views::take(badarg)(x); // { dg-error "deleted" } - views::drop(badarg)(x); // { dg-error "deleted" } - (views::take(badarg) | views::all)(x); // { dg-error "deleted" } - (views::drop(badarg) | views::all)(x); // { dg-error "deleted" } + views::take(badarg)(x); // { dg-error "deleted|no match" } + views::drop(badarg)(x); // { dg-error "deleted|no match" } + (views::take(badarg) | views::all)(x); // { dg-error "deleted|no match" } + (views::drop(badarg) | views::all)(x); // { dg-error "deleted|no match" } } void diff --git a/libstdc++-v3/testsuite/std/ranges/adaptors/lazy_split_neg.cc b/libstdc++-v3/testsuite/std/ranges/adaptors/lazy_split_neg.cc index 683ea76da07..85632759fcc 100644 --- a/libstdc++-v3/testsuite/std/ranges/adaptors/lazy_split_neg.cc +++ b/libstdc++-v3/testsuite/std/ranges/adaptors/lazy_split_neg.cc @@ -38,7 +38,7 @@ test02() { using namespace std::literals; auto x = "the quick brown fox"sv; - auto v1 = views::lazy_split(std::initializer_list<char>{' ', ' '})(x); // { dg-error "deleted" } + auto v1 = views::lazy_split(std::initializer_list<char>{' ', ' '})(x); // { dg-error "deleted|no match" } auto v2 = x | views::lazy_split(std::initializer_list<char>{' ', ' '}); // { dg-error "no match" } }