Created on 2022-06-15.00:00:00 last changed 1 week ago
Proposed resolution:
This wording is relative to N4910.
Modify [range.common.view] as indicated:
namespace std::ranges { template<view V> requires (!common_range<V> && copyable<iterator_t<V>>) class common_view : public view_interface<common_view<V>> { private: V base_ = V(); // exposition only public: […] constexpr auto begin() { if constexpr (random_access_range<V> && sized_range<V>) return ranges::begin(base_); else return common_iterator<iterator_t<V>, sentinel_t<V>>(ranges::begin(base_)); } constexpr auto begin() const requires range<const V> { if constexpr (random_access_range<const V> && sized_range<const V>) return ranges::begin(base_); else return common_iterator<iterator_t<const V>, sentinel_t<const V>>(ranges::begin(base_)); } constexpr auto end() { if constexpr (random_access_range<V> && sized_range<V>) return ranges::begin(base_) + range_difference_t<V>(size())ranges::size(base_); else return common_iterator<iterator_t<V>, sentinel_t<V>>(ranges::end(base_)); } constexpr auto end() const requires range<const V> { if constexpr (random_access_range<const V> && sized_range<const V>) return ranges::begin(base_) + range_difference_t<const V>(size())ranges::size(base_); else return common_iterator<iterator_t<const V>, sentinel_t<const V>>(ranges::end(base_)); } constexpr auto size() requires sized_range<V> { return ranges::size(base_); } constexpr auto size() const requires sized_range<const V> { return ranges::size(base_); } }; […] }
In view of the fact that random access iterators are only required to work with its difference type, P2393R1 improves the wording of take_view, which first convert the integer type to difference type and then operate with the iterator. However, the paper omits the handling of random access iterators in common_view::end, which directly operates on the return types of ranges::begin and ranges::size. We should improve this, too.
History | |||
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Date | User | Action | Args |
2022-06-15 18:16:27 | admin | set | messages: + msg12505 |
2022-06-15 00:00:00 | admin | create |