* [PATCH 1/3] libstdc++: Implement P1994R1 changes to ranges::elements_view
@ 2020-08-26 20:44 Patrick Palka
2020-08-26 20:44 ` [PATCH 2/3] libstdc++: elements_view's sentinel and iterator not comparable [LWG 3406] Patrick Palka
` (2 more replies)
0 siblings, 3 replies; 6+ messages in thread
From: Patrick Palka @ 2020-08-26 20:44 UTC (permalink / raw)
To: gcc-patches; +Cc: libstdc++, Patrick Palka
The example from the paper doesn't compile without the proposed
resolution for LWG 3406, so we'll add a testcase for this once the
proposed resolution is in.
libstdc++-v3/ChangeLog:
P1994R1: elements_view needs its own sentinel.
* include/std/ranges (elements_view::end): Replace these two
overloads with four new overloads.
(elements_view::_Iterator::operator==): Remove.
(elements_view::_Iterator::operator-): Likewise.
(elements_view::_Sentinel): Define.
---
libstdc++-v3/include/std/ranges | 74 ++++++++++++++++++++++++++-------
1 file changed, 60 insertions(+), 14 deletions(-)
diff --git a/libstdc++-v3/include/std/ranges b/libstdc++-v3/include/std/ranges
index 9d22b138082..efa8d2cf9f4 100644
--- a/libstdc++-v3/include/std/ranges
+++ b/libstdc++-v3/include/std/ranges
@@ -3366,12 +3366,20 @@ namespace views
{ return _Iterator<true>(ranges::begin(_M_base)); }
constexpr auto
- end() requires (!__detail::__simple_view<_Vp>)
- { return ranges::end(_M_base); }
+ end()
+ { return _Sentinel<false>{ranges::end(_M_base)}; }
constexpr auto
- end() const requires __detail::__simple_view<_Vp>
- { return ranges::end(_M_base); }
+ end() requires common_range<_Vp>
+ { return _Iterator<false>{ranges::end(_M_base)}; }
+
+ constexpr auto
+ end() const requires range<const _Vp>
+ { return _Sentinel<true>{ranges::end(_M_base)}; }
+
+ constexpr auto
+ end() const requires common_range<const _Vp>
+ { return _Iterator<true>{ranges::end(_M_base)}; }
constexpr auto
size() requires sized_range<_Vp>
@@ -3382,6 +3390,9 @@ namespace views
{ return ranges::size(_M_base); }
private:
+ template<bool _Const>
+ struct _Sentinel;
+
template<bool _Const>
struct _Iterator
{
@@ -3484,10 +3495,6 @@ namespace views
requires equality_comparable<iterator_t<_Base>>
{ return __x._M_current == __y._M_current; }
- friend constexpr bool
- operator==(const _Iterator& __x, const sentinel_t<_Base>& __y)
- { return __x._M_current == __y; }
-
friend constexpr bool
operator<(const _Iterator& __x, const _Iterator& __y)
requires random_access_range<_Base>
@@ -3536,15 +3543,54 @@ namespace views
requires random_access_range<_Base>
{ return __x._M_current - __y._M_current; }
- friend constexpr difference_type
- operator-(const _Iterator<_Const>& __x, const sentinel_t<_Base>& __y)
+ friend _Sentinel<_Const>;
+ };
+
+ template<bool _Const>
+ struct _Sentinel
+ {
+ private:
+ constexpr bool
+ _M_equal(const _Iterator<_Const>& __x) const
+ { return __x._M_current == _M_end; }
+
+ using _Base = __detail::__maybe_const_t<_Const, _Vp>;
+ sentinel_t<_Base> _M_end = sentinel_t<_Base>();
+
+ public:
+ _Sentinel() = default;
+
+ constexpr explicit
+ _Sentinel(sentinel_t<_Base> __end)
+ : _M_end(std::move(__end))
+ { }
+
+ constexpr
+ _Sentinel(_Sentinel<!_Const> __other)
+ requires _Const
+ && convertible_to<sentinel_t<_Vp>, sentinel_t<_Base>>
+ : _M_end(std::move(__other._M_end))
+ { }
+
+ constexpr sentinel_t<_Base>
+ base() const
+ { return _M_end; }
+
+ friend constexpr bool
+ operator==(const _Iterator<_Const>& __x, const _Sentinel& __y)
+ { return __y._M_equal(__x); }
+
+ friend constexpr range_difference_t<_Base>
+ operator-(const _Iterator<_Const>& __x, const _Sentinel& __y)
requires sized_sentinel_for<sentinel_t<_Base>, iterator_t<_Base>>
- { return __x._M_current - __y; }
+ { return __x._M_current - __y._M_end; }
- friend constexpr difference_type
- operator-(const sentinel_t<_Base>& __x, const _Iterator<_Const>& __y)
+ friend constexpr range_difference_t<_Base>
+ operator-(const _Sentinel& __x, const _Iterator<_Const>& __y)
requires sized_sentinel_for<sentinel_t<_Base>, iterator_t<_Base>>
- { return -(__y - __x); }
+ { return __x._M_end - __y._M_current; }
+
+ friend _Sentinel<!_Const>;
};
_Vp _M_base = _Vp();
--
2.28.0.337.ge9b77c84a0
^ permalink raw reply [flat|nested] 6+ messages in thread
* [PATCH 2/3] libstdc++: elements_view's sentinel and iterator not comparable [LWG 3406]
2020-08-26 20:44 [PATCH 1/3] libstdc++: Implement P1994R1 changes to ranges::elements_view Patrick Palka
@ 2020-08-26 20:44 ` Patrick Palka
2020-08-26 20:57 ` Jonathan Wakely
2020-08-26 20:44 ` [PATCH 3/3] libstdc++: Implement remaining piece of LWG 3448 Patrick Palka
2020-08-26 20:56 ` [PATCH 1/3] libstdc++: Implement P1994R1 changes to ranges::elements_view Jonathan Wakely
2 siblings, 1 reply; 6+ messages in thread
From: Patrick Palka @ 2020-08-26 20:44 UTC (permalink / raw)
To: gcc-patches; +Cc: libstdc++, Patrick Palka
This implements the proposed resolution for LWG 3406 and adds a testcase
for the example from P1994R1.
libstdc++-v3/ChangeLog:
LWG 3406
* include/std/ranges (elements_view::begin): Adjust constraints.
(elements_view::end): Likewise.
(elements_view::_Sentinel::operator==): Templatize to take both
_Iterator<true> and _Iterator<false>.
(elements_view::_Sentinel::operator-): Likewise.
* testsuite/std/ranges/adaptors/elements.cc: Add testcase for
the example from P1994R1.
* testsuite/std/range/adaptors/lwg3406.cc: New test.
---
libstdc++-v3/include/std/ranges | 39 ++++++++-------
.../testsuite/std/ranges/adaptors/elements.cc | 22 +++++++++
.../testsuite/std/ranges/adaptors/lwg3406.cc | 48 +++++++++++++++++++
3 files changed, 93 insertions(+), 16 deletions(-)
create mode 100644 libstdc++-v3/testsuite/std/ranges/adaptors/lwg3406.cc
diff --git a/libstdc++-v3/include/std/ranges b/libstdc++-v3/include/std/ranges
index efa8d2cf9f4..42028354b81 100644
--- a/libstdc++-v3/include/std/ranges
+++ b/libstdc++-v3/include/std/ranges
@@ -3362,15 +3362,15 @@ namespace views
{ return _Iterator<false>(ranges::begin(_M_base)); }
constexpr auto
- begin() const requires __detail::__simple_view<_Vp>
+ begin() const requires range<const _Vp>
{ return _Iterator<true>(ranges::begin(_M_base)); }
constexpr auto
- end()
+ end() requires (!__detail::__simple_view<_Vp> && !common_range<_Vp>)
{ return _Sentinel<false>{ranges::end(_M_base)}; }
constexpr auto
- end() requires common_range<_Vp>
+ end() requires (!__detail::__simple_view<_Vp> && common_range<_Vp>)
{ return _Iterator<false>{ranges::end(_M_base)}; }
constexpr auto
@@ -3576,19 +3576,26 @@ namespace views
base() const
{ return _M_end; }
- friend constexpr bool
- operator==(const _Iterator<_Const>& __x, const _Sentinel& __y)
- { return __y._M_equal(__x); }
-
- friend constexpr range_difference_t<_Base>
- operator-(const _Iterator<_Const>& __x, const _Sentinel& __y)
- requires sized_sentinel_for<sentinel_t<_Base>, iterator_t<_Base>>
- { return __x._M_current - __y._M_end; }
-
- friend constexpr range_difference_t<_Base>
- operator-(const _Sentinel& __x, const _Iterator<_Const>& __y)
- requires sized_sentinel_for<sentinel_t<_Base>, iterator_t<_Base>>
- { return __x._M_end - __y._M_current; }
+ template<bool _Const2>
+ requires sentinel_for<sentinel_t<_Base>,
+ iterator_t<__detail::__maybe_const_t<_Const2, _Vp>>>
+ friend constexpr bool
+ operator==(const _Iterator<_Const2>& __x, const _Sentinel& __y)
+ { return __y._M_equal(__x); }
+
+ template<bool _Const2,
+ typename _Base2 = __detail::__maybe_const_t<_Const2, _Vp>>
+ requires sized_sentinel_for<sentinel_t<_Base>, iterator_t<_Base2>>
+ friend constexpr range_difference_t<_Base2>
+ operator-(const _Iterator<_Const2>& __x, const _Sentinel& __y)
+ { return __x._M_current - __y._M_end; }
+
+ template<bool _Const2,
+ typename _Base2 = __detail::__maybe_const_t<_Const2, _Vp>>
+ requires sized_sentinel_for<sentinel_t<_Base>, iterator_t<_Base2>>
+ friend constexpr range_difference_t<_Base>
+ operator-(const _Sentinel& __x, const _Iterator<_Const2>& __y)
+ { return __x._M_end - __y._M_current; }
friend _Sentinel<!_Const>;
};
diff --git a/libstdc++-v3/testsuite/std/ranges/adaptors/elements.cc b/libstdc++-v3/testsuite/std/ranges/adaptors/elements.cc
index d846c4cf33e..af5c2d43bb6 100644
--- a/libstdc++-v3/testsuite/std/ranges/adaptors/elements.cc
+++ b/libstdc++-v3/testsuite/std/ranges/adaptors/elements.cc
@@ -45,8 +45,30 @@ test01()
VERIFY( ranges::equal(v1, x | views::values) );
}
+struct S
+{
+ friend bool
+ operator==(std::input_iterator auto const& i, S)
+ { return std::get<1>(*i) == 0; }
+};
+
+void
+test02()
+{
+ // This verifies that P1994R1 (and LWG3406) is implemented.
+ std::pair<std::pair<char, int>, long> x[]
+ = {{{1,2},3l}, {{1,0},2l}, {{1,2},0l}};
+ ranges::subrange r{ranges::begin(x), S{}};
+
+ auto v = r | views::keys;
+ VERIFY( ranges::equal(v, (std::pair<char, int>[]){{1,2},{1,0}}) );
+ ranges::subrange v2 = {ranges::begin(v), S{}};
+ VERIFY( ranges::equal(v2, (std::pair<char, int>[]){{1,2}}) );
+}
+
int
main()
{
test01();
+ test02();
}
diff --git a/libstdc++-v3/testsuite/std/ranges/adaptors/lwg3406.cc b/libstdc++-v3/testsuite/std/ranges/adaptors/lwg3406.cc
new file mode 100644
index 00000000000..d36db22aad5
--- /dev/null
+++ b/libstdc++-v3/testsuite/std/ranges/adaptors/lwg3406.cc
@@ -0,0 +1,48 @@
+// Copyright (C) 2020 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library. This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License along
+// with this library; see the file COPYING3. If not see
+// <http://www.gnu.org/licenses/>.
+
+// { dg-options "-std=gnu++2a" }
+// { dg-do compile { target c++2a } }
+
+#include <ranges>
+#include <testsuite_hooks.h>
+
+namespace ranges = std::ranges;
+namespace views = std::views;
+
+void
+test01()
+{
+ std::tuple<int, int> x[] = {{0,0}};
+ auto v = x | views::elements<0>;
+ bool b = ranges::cbegin(v) == ranges::end(v);
+}
+
+void
+test02()
+{
+ std::tuple x = {0, 1};
+ auto v = views::single(x) | views::elements<0>;
+ auto i = ranges::cbegin(v);
+}
+
+int
+main()
+{
+ test01();
+ test02();
+}
--
2.28.0.337.ge9b77c84a0
^ permalink raw reply [flat|nested] 6+ messages in thread
* [PATCH 3/3] libstdc++: Implement remaining piece of LWG 3448
2020-08-26 20:44 [PATCH 1/3] libstdc++: Implement P1994R1 changes to ranges::elements_view Patrick Palka
2020-08-26 20:44 ` [PATCH 2/3] libstdc++: elements_view's sentinel and iterator not comparable [LWG 3406] Patrick Palka
@ 2020-08-26 20:44 ` Patrick Palka
2020-08-26 20:57 ` Jonathan Wakely
2020-08-26 20:56 ` [PATCH 1/3] libstdc++: Implement P1994R1 changes to ranges::elements_view Jonathan Wakely
2 siblings, 1 reply; 6+ messages in thread
From: Patrick Palka @ 2020-08-26 20:44 UTC (permalink / raw)
To: gcc-patches; +Cc: libstdc++, Patrick Palka
Almost all of the proposed resolution for LWG 3448 is already
implemented; the only part left is to adjust the return type of
transform_view::sentinel::operator-.
libstdc++-v3/ChangeLog:
LWG 3448
PR libstdc++/95322
* include/std/ranges (transform_view::__distance_from): Give
this a deduced return type.
(transform_view::sentinel::operator-): Adjust the return type so
that it's based on the constness of the iterator rather than
that of the sentinel.
* testsuite/std/ranges/adaptors/95322.cc: Refer to LWG 3488.
---
libstdc++-v3/include/std/ranges | 18 +++++++++---------
.../testsuite/std/ranges/adaptors/95322.cc | 2 +-
2 files changed, 10 insertions(+), 10 deletions(-)
diff --git a/libstdc++-v3/include/std/ranges b/libstdc++-v3/include/std/ranges
index 42028354b81..2d0017f1750 100644
--- a/libstdc++-v3/include/std/ranges
+++ b/libstdc++-v3/include/std/ranges
@@ -1865,7 +1865,7 @@ namespace views
using _Base = __detail::__maybe_const_t<_Const, _Vp>;
template<bool _Const2>
- constexpr range_difference_t<_Base>
+ constexpr auto
__distance_from(const _Iterator<_Const2>& __i) const
{ return _M_end - __i._M_current; }
@@ -1902,17 +1902,17 @@ namespace views
operator==(const _Iterator<_Const2>& __x, const _Sentinel& __y)
{ return __y.__equal(__x); }
- template<bool _Const2>
- requires sized_sentinel_for<sentinel_t<_Base>,
- iterator_t<__detail::__maybe_const_t<_Const2, _Vp>>>
- friend constexpr range_difference_t<_Base>
+ template<bool _Const2,
+ typename _Base2 = __detail::__maybe_const_t<_Const2, _Vp>>
+ requires sized_sentinel_for<sentinel_t<_Base>, iterator_t<_Base2>>
+ friend constexpr range_difference_t<_Base2>
operator-(const _Iterator<_Const2>& __x, const _Sentinel& __y)
{ return -__y.__distance_from(__x); }
- template<bool _Const2>
- requires sized_sentinel_for<sentinel_t<_Base>,
- iterator_t<__detail::__maybe_const_t<_Const2, _Vp>>>
- friend constexpr range_difference_t<_Base>
+ template<bool _Const2,
+ typename _Base2 = __detail::__maybe_const_t<_Const2, _Vp>>
+ requires sized_sentinel_for<sentinel_t<_Base>, iterator_t<_Base2>>
+ friend constexpr range_difference_t<_Base2>
operator-(const _Sentinel& __y, const _Iterator<_Const2>& __x)
{ return __y.__distance_from(__x); }
diff --git a/libstdc++-v3/testsuite/std/ranges/adaptors/95322.cc b/libstdc++-v3/testsuite/std/ranges/adaptors/95322.cc
index 9279d5520a8..67bc7d33917 100644
--- a/libstdc++-v3/testsuite/std/ranges/adaptors/95322.cc
+++ b/libstdc++-v3/testsuite/std/ranges/adaptors/95322.cc
@@ -26,7 +26,7 @@ using __gnu_test::test_forward_range;
void
test01()
{
- // PR libstdc++/95322
+ // PR libstdc++/95322 and LWG 3488
int a[2]{1, 2};
test_forward_range<int> v{a};
auto view1 = v | std::views::take(2);
--
2.28.0.337.ge9b77c84a0
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH 1/3] libstdc++: Implement P1994R1 changes to ranges::elements_view
2020-08-26 20:44 [PATCH 1/3] libstdc++: Implement P1994R1 changes to ranges::elements_view Patrick Palka
2020-08-26 20:44 ` [PATCH 2/3] libstdc++: elements_view's sentinel and iterator not comparable [LWG 3406] Patrick Palka
2020-08-26 20:44 ` [PATCH 3/3] libstdc++: Implement remaining piece of LWG 3448 Patrick Palka
@ 2020-08-26 20:56 ` Jonathan Wakely
2 siblings, 0 replies; 6+ messages in thread
From: Jonathan Wakely @ 2020-08-26 20:56 UTC (permalink / raw)
To: Patrick Palka; +Cc: gcc-patches, libstdc++
On 26/08/20 16:44 -0400, Patrick Palka via Libstdc++ wrote:
>The example from the paper doesn't compile without the proposed
>resolution for LWG 3406, so we'll add a testcase for this once the
>proposed resolution is in.
>
>libstdc++-v3/ChangeLog:
>
> P1994R1: elements_view needs its own sentinel.
> * include/std/ranges (elements_view::end): Replace these two
> overloads with four new overloads.
> (elements_view::_Iterator::operator==): Remove.
> (elements_view::_Iterator::operator-): Likewise.
> (elements_view::_Sentinel): Define.
OK, thanks.
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH 2/3] libstdc++: elements_view's sentinel and iterator not comparable [LWG 3406]
2020-08-26 20:44 ` [PATCH 2/3] libstdc++: elements_view's sentinel and iterator not comparable [LWG 3406] Patrick Palka
@ 2020-08-26 20:57 ` Jonathan Wakely
0 siblings, 0 replies; 6+ messages in thread
From: Jonathan Wakely @ 2020-08-26 20:57 UTC (permalink / raw)
To: Patrick Palka; +Cc: gcc-patches, libstdc++
On 26/08/20 16:44 -0400, Patrick Palka via Libstdc++ wrote:
>This implements the proposed resolution for LWG 3406 and adds a testcase
>for the example from P1994R1.
>
>libstdc++-v3/ChangeLog:
>
> LWG 3406
> * include/std/ranges (elements_view::begin): Adjust constraints.
> (elements_view::end): Likewise.
> (elements_view::_Sentinel::operator==): Templatize to take both
> _Iterator<true> and _Iterator<false>.
> (elements_view::_Sentinel::operator-): Likewise.
> * testsuite/std/ranges/adaptors/elements.cc: Add testcase for
> the example from P1994R1.
> * testsuite/std/range/adaptors/lwg3406.cc: New test.
OK, thanks.
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH 3/3] libstdc++: Implement remaining piece of LWG 3448
2020-08-26 20:44 ` [PATCH 3/3] libstdc++: Implement remaining piece of LWG 3448 Patrick Palka
@ 2020-08-26 20:57 ` Jonathan Wakely
0 siblings, 0 replies; 6+ messages in thread
From: Jonathan Wakely @ 2020-08-26 20:57 UTC (permalink / raw)
To: Patrick Palka; +Cc: gcc-patches, libstdc++
On 26/08/20 16:44 -0400, Patrick Palka via Libstdc++ wrote:
>Almost all of the proposed resolution for LWG 3448 is already
>implemented; the only part left is to adjust the return type of
>transform_view::sentinel::operator-.
>
>libstdc++-v3/ChangeLog:
>
> LWG 3448
> PR libstdc++/95322
> * include/std/ranges (transform_view::__distance_from): Give
> this a deduced return type.
> (transform_view::sentinel::operator-): Adjust the return type so
> that it's based on the constness of the iterator rather than
> that of the sentinel.
> * testsuite/std/ranges/adaptors/95322.cc: Refer to LWG 3488.
Also OK, thanks for fixing these.
^ permalink raw reply [flat|nested] 6+ messages in thread
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