From Jason Turner

[range.utility.conv.to]

C++23 → Trunk 1.4 KB 14 lines
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Archived: C++23
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  1. tmp/tmp6ptykesn/{from.md → to.md} +6 -5
tmp/tmp6ptykesn/{from.md → to.md} RENAMED
@@ -32,21 +32,22 @@ the following manner:
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  ``` cpp
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  C(ranges::begin(r), ranges::end(r), std::forward<Args>(args)...)
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  ```
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  - Otherwise, if
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  - `constructible_from<C, Args...>` is `true`, and
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- - *`container-insertable`*`<C, range_reference_t<R>>` is `true`:
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  ``` cpp
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  C c(std::forward<Args>(args)...);
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- if constexpr (sized_range<R> && reservable-container<C>)
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- c.reserve(static_cast<range_size_t<C>>(ranges::size(r)));
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- ranges::copy(r, container-inserter<range_reference_t<R>>(c));
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  ```
 
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  - Otherwise, if `input_range<range_reference_t<R>>` is `true`:
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  ``` cpp
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- to<C>(r | views::transform([](auto&& elem) {
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  return to<range_value_t<C>>(std::forward<decltype(elem)>(elem));
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  }), std::forward<Args>(args)...);
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  ```
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  - Otherwise, the program is ill-formed.
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  ``` cpp
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  C(ranges::begin(r), ranges::end(r), std::forward<Args>(args)...)
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  ```
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  - Otherwise, if
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  - `constructible_from<C, Args...>` is `true`, and
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+ - *`container-appendable`*`<C, range_reference_t<R>>` is `true`:
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  ``` cpp
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  C c(std::forward<Args>(args)...);
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+ if constexpr (approximately_sized_range<R> && reservable-container<C>)
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+ c.reserve(static_cast<range_size_t<C>>(ranges::reserve_hint(r)));
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+ ranges::for_each(r, container-append(c));
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  ```
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+ - Otherwise, the program is ill-formed.
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  - Otherwise, if `input_range<range_reference_t<R>>` is `true`:
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  ``` cpp
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+ to<C>(ref_view(r) | views::transform([](auto&& elem) {
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  return to<range_value_t<C>>(std::forward<decltype(elem)>(elem));
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  }), std::forward<Args>(args)...);
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  ```
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  - Otherwise, the program is ill-formed.
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