From Jason Turner

[range.filter.iterator]

C++20 → C++23 3.1 KB 26 lines
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Archived: C++20 | C++23
Markdown: C++20 | C++23
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  1. tmp/tmpg48ktvf_/{from.md → to.md} +11 -9
tmp/tmpg48ktvf_/{from.md → to.md} RENAMED
@@ -6,21 +6,21 @@ namespace std::ranges {
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  requires view<V> && is_object_v<Pred>
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  class filter_view<V, Pred>::iterator {
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  private:
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  iterator_t<V> current_ = iterator_t<V>(); // exposition only
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  filter_view* parent_ = nullptr; // exposition only
 
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  public:
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- using iterator_concept = see below;
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- using iterator_category = see below;
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  using value_type = range_value_t<V>;
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  using difference_type = range_difference_t<V>;
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- iterator() = default;
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  constexpr iterator(filter_view& parent, iterator_t<V> current);
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- constexpr iterator_t<V> base() const &
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- requires copyable<iterator_t<V>>;
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  constexpr iterator_t<V> base() &&;
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  constexpr range_reference_t<V> operator*() const;
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  constexpr iterator_t<V> operator->() const
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  requires has-arrow<iterator_t<V>> && copyable<iterator_t<V>>;
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@@ -34,10 +34,11 @@ namespace std::ranges {
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  friend constexpr bool operator==(const iterator& x, const iterator& y)
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  requires equality_comparable<iterator_t<V>>;
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  friend constexpr range_rvalue_reference_t<V> iter_move(const iterator& i)
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  noexcept(noexcept(ranges::iter_move(i.current_)));
 
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  friend constexpr void iter_swap(const iterator& x, const iterator& y)
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  noexcept(noexcept(ranges::iter_swap(x.current_, y.current_)))
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  requires indirectly_swappable<iterator_t<V>>;
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  };
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  }
@@ -53,11 +54,13 @@ not satisfy the filter predicate.
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  `bidirectional_iterator_tag`.
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  - Otherwise, if `V` models `forward_range`, then `iterator_concept`
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  denotes `forward_iterator_tag`.
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  - Otherwise, `iterator_concept` denotes `input_iterator_tag`.
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- `iterator::iterator_category` is defined as follows:
 
 
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  - Let `C` denote the type
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  `iterator_traits<iterator_t<V>>::iterator_category`.
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  - If `C` models `derived_from<bidirectional_iterator_tag>`, then
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  `iterator_category` denotes `bidirectional_iterator_tag`.
@@ -71,21 +74,20 @@ constexpr iterator(filter_view& parent, iterator_t<V> current);
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  *Effects:* Initializes *current\_* with `std::move(current)` and
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  *parent\_* with `addressof(parent)`.
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  ``` cpp
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- constexpr iterator_t<V> base() const &
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- requires copyable<iterator_t<V>>;
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  ```
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  *Effects:* Equivalent to: `return `*`current_`*`;`
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  ``` cpp
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  constexpr iterator_t<V> base() &&;
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  ```
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- *Effects:* Equivalent to: `return std::move(current_);`
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  ``` cpp
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  constexpr range_reference_t<V> operator*() const;
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  ```
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  requires view<V> && is_object_v<Pred>
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  class filter_view<V, Pred>::iterator {
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  private:
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  iterator_t<V> current_ = iterator_t<V>(); // exposition only
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  filter_view* parent_ = nullptr; // exposition only
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+
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  public:
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+ using iterator_concept = see belownc;
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+ using iterator_category = see belownc; // not always present
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  using value_type = range_value_t<V>;
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  using difference_type = range_difference_t<V>;
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+ iterator() requires default_initializable<iterator_t<V>> = default;
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  constexpr iterator(filter_view& parent, iterator_t<V> current);
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+ constexpr const iterator_t<V>& base() const & noexcept;
 
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  constexpr iterator_t<V> base() &&;
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  constexpr range_reference_t<V> operator*() const;
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  constexpr iterator_t<V> operator->() const
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  requires has-arrow<iterator_t<V>> && copyable<iterator_t<V>>;
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  friend constexpr bool operator==(const iterator& x, const iterator& y)
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  requires equality_comparable<iterator_t<V>>;
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  friend constexpr range_rvalue_reference_t<V> iter_move(const iterator& i)
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  noexcept(noexcept(ranges::iter_move(i.current_)));
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+
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  friend constexpr void iter_swap(const iterator& x, const iterator& y)
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  noexcept(noexcept(ranges::iter_swap(x.current_, y.current_)))
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  requires indirectly_swappable<iterator_t<V>>;
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  };
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  }
 
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  `bidirectional_iterator_tag`.
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  - Otherwise, if `V` models `forward_range`, then `iterator_concept`
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  denotes `forward_iterator_tag`.
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  - Otherwise, `iterator_concept` denotes `input_iterator_tag`.
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+ The member *typedef-name* `iterator_category` is defined if and only if
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+ `V` models `forward_range`. In that case, `iterator::iterator_category`
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+ is defined as follows:
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  - Let `C` denote the type
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  `iterator_traits<iterator_t<V>>::iterator_category`.
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  - If `C` models `derived_from<bidirectional_iterator_tag>`, then
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  `iterator_category` denotes `bidirectional_iterator_tag`.
 
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  *Effects:* Initializes *current\_* with `std::move(current)` and
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  *parent\_* with `addressof(parent)`.
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  ``` cpp
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+ constexpr const iterator_t<V>& base() const & noexcept;
 
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  ```
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  *Effects:* Equivalent to: `return `*`current_`*`;`
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  ``` cpp
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  constexpr iterator_t<V> base() &&;
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  ```
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+ *Effects:* Equivalent to: `return std::move(`*`current_`*`);`
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  ``` cpp
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  constexpr range_reference_t<V> operator*() const;
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  ```
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