From Jason Turner

[range.transform.view]

C++17 → C++20 3.5 KB 125 lines
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Archived: C++17 | C++20
Markdown: C++17 | C++20
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  1. tmp/tmpfssro9ot/{from.md → to.md} +122 -0
tmp/tmpfssro9ot/{from.md → to.md} RENAMED
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+ #### Class template `transform_view` <a id="range.transform.view">[[range.transform.view]]</a>
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+
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+ ``` cpp
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+ namespace std::ranges {
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+ template<input_range V, copy_constructible F>
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+ requires view<V> && is_object_v<F> &&
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+ regular_invocable<F&, range_reference_t<V>> &&
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+ can-reference<invoke_result_t<F&, range_reference_t<V>>>
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+ class transform_view : public view_interface<transform_view<V, F>> {
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+ private:
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+ // [range.transform.iterator], class template transform_view::iterator
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+ template<bool> struct iterator; // exposition only
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+ // [range.transform.sentinel], class template transform_view::sentinel
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+ template<bool> struct sentinel; // exposition only
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+
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+ V base_ = V(); // exposition only
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+ semiregular-box<F> fun_; // exposition only
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+
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+ public:
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+ transform_view() = default;
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+ constexpr transform_view(V base, F fun);
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+
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+ constexpr V base() const& requires copy_constructible<V> { return base_; }
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+ constexpr V base() && { return std::move(base_); }
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+
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+ constexpr iterator<false> begin();
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+ constexpr iterator<true> begin() const
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+ requires range<const V> &&
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+ regular_invocable<const F&, range_reference_t<const V>>;
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+
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+ constexpr sentinel<false> end();
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+ constexpr iterator<false> end() requires common_range<V>;
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+ constexpr sentinel<true> end() const
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+ requires range<const V> &&
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+ regular_invocable<const F&, range_reference_t<const V>>;
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+ constexpr iterator<true> end() const
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+ requires common_range<const V> &&
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+ regular_invocable<const F&, range_reference_t<const V>>;
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+
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+ constexpr auto size() requires sized_range<V> { return ranges::size(base_); }
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+ constexpr auto size() const requires sized_range<const V>
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+ { return ranges::size(base_); }
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+ };
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+
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+ template<class R, class F>
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+ transform_view(R&&, F) -> transform_view<views::all_t<R>, F>;
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+ }
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+ ```
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+
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+ ``` cpp
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+ constexpr transform_view(V base, F fun);
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+ ```
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+
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+ *Effects:* Initializes *base\_* with `std::move(base)` and *fun\_* with
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+ `std::move(fun)`.
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+
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+ ``` cpp
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+ constexpr iterator<false> begin();
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+ ```
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+
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+ *Effects:* Equivalent to:
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+
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+ ``` cpp
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+ return iterator<false>{*this, ranges::begin(base_)};
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+ ```
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+
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+ ``` cpp
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+ constexpr iterator<true> begin() const
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+ requires range<const V> &&
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+ regular_invocable<const F&, range_reference_t<const V>>;
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+ ```
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+
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+ *Effects:* Equivalent to:
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+
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+ ``` cpp
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+ return iterator<true>{*this, ranges::begin(base_)};
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+ ```
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+
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+ ``` cpp
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+ constexpr sentinel<false> end();
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+ ```
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+
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+ *Effects:* Equivalent to:
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+
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+ ``` cpp
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+ return sentinel<false>{ranges::end(base_)};
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+ ```
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+
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+ ``` cpp
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+ constexpr iterator<false> end() requires common_range<V>;
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+ ```
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+
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+ *Effects:* Equivalent to:
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+
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+ ``` cpp
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+ return iterator<false>{*this, ranges::end(base_)};
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+ ```
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+
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+ ``` cpp
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+ constexpr sentinel<true> end() const
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+ requires range<const V> &&
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+ regular_invocable<const F&, range_reference_t<const V>>;
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+ ```
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+
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+ *Effects:* Equivalent to:
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+
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+ ``` cpp
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+ return sentinel<true>{ranges::end(base_)};
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+ ```
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+
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+ ``` cpp
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+ constexpr iterator<true> end() const
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+ requires common_range<const V> &&
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+ regular_invocable<const F&, range_reference_t<const V>>;
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+ ```
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+
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+ *Effects:* Equivalent to:
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+
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+ ``` cpp
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+ return iterator<true>{*this, ranges::end(base_)};
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+ ```
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+