From Jason Turner

[range.adjacent.transform]

C++23 → Trunk 3.6 KB 31 lines
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Markdown: C++23 | Trunk
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  1. tmp/tmpaqrbw8ah/{from.md → to.md} +16 -7
tmp/tmpaqrbw8ah/{from.md → to.md} RENAMED
@@ -10,13 +10,14 @@ resulting view is empty.
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  The name `views::adjacent_transform<N>` denotes a range adaptor object
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  [[range.adaptor.object]]. Given subexpressions `E` and `F` and a
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  constant expression `N`:
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- - If `N` is equal to `0`, `views::adjacent_transform<N>(E, F)` is
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- expression-equivalent to `((void)E, views::zip_transform(F))`, except
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- that the evaluations of `E` and `F` are indeterminately sequenced.
 
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  - Otherwise, the expression `views::adjacent_transform<N>(E, F)` is
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  expression-equivalent to
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  `adjacent_transform_view<views::all_t<decltype((E))>, decay_t<decltype((F))>, N>(E, F)`.
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  [*Example 1*:
@@ -57,11 +58,11 @@ namespace std::ranges {
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  public:
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  adjacent_transform_view() = default;
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  constexpr explicit adjacent_transform_view(V base, F fun);
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- constexpr V base() const & requires copy_constructible<InnerView> { return inner_.base(); }
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  constexpr V base() && { return std::move(inner_).base(); }
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  constexpr auto begin() {
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  return iterator<false>(*this, inner_.begin());
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  }
@@ -95,10 +96,18 @@ namespace std::ranges {
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  }
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  constexpr auto size() const requires sized_range<const InnerView> {
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  return inner_.size();
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  }
 
 
 
 
 
 
 
 
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  };
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  }
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  ```
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  ``` cpp
@@ -125,11 +134,11 @@ namespace std::ranges {
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  constexpr iterator(Parent& parent, inner-iterator<Const> inner); // exposition only
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  public:
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  using iterator_category = see below;
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- using iterator_concept = typename inner-iterator<Const>::iterator_concept;
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  using value_type =
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  remove_cvref_t<invoke_result_t<maybe-const<Const, F>&,
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  REPEAT(range_reference_t<Base>, N)...>>;
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  using difference_type = range_difference_t<Base>;
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@@ -399,11 +408,11 @@ constexpr sentinel(sentinel<!Const> i)
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  template<bool OtherConst>
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  requires sentinel_for<inner-sentinel<Const>, inner-iterator<OtherConst>>
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  friend constexpr bool operator==(const iterator<OtherConst>& x, const sentinel& y);
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  ```
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- *Effects:* Equivalent to `return x.`*`inner_`*` == y.`*`inner_`*`;`
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  ``` cpp
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  template<bool OtherConst>
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  requires sized_sentinel_for<inner-sentinel<Const>, inner-iterator<OtherConst>>
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  friend constexpr range_difference_t<maybe-const<OtherConst, InnerView>>
@@ -413,7 +422,7 @@ template<bool OtherConst>
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  requires sized_sentinel_for<inner-sentinel<Const>, inner-iterator<OtherConst>>
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  friend constexpr range_difference_t<maybe-const<OtherConst, InnerView>>
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  operator-(const sentinel& x, const iterator<OtherConst>& y);
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  ```
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- *Effects:* Equivalent to `return x.`*`inner_`*` - y.`*`inner_`*`;`
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  The name `views::adjacent_transform<N>` denotes a range adaptor object
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  [[range.adaptor.object]]. Given subexpressions `E` and `F` and a
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  constant expression `N`:
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+ - If `N` is equal to `0` and `decltype((E))` models `forward_range`,
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+ `views::adjacent_transform<N>(E, F)` is expression-equivalent to
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+ `((void)E, views::zip_transform(F))`, except that the evaluations of
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+ `E` and `F` are indeterminately sequenced.
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  - Otherwise, the expression `views::adjacent_transform<N>(E, F)` is
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  expression-equivalent to
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  `adjacent_transform_view<views::all_t<decltype((E))>, decay_t<decltype((F))>, N>(E, F)`.
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  [*Example 1*:
 
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  public:
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  adjacent_transform_view() = default;
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  constexpr explicit adjacent_transform_view(V base, F fun);
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+ constexpr V base() const & requires copy_constructible<V> { return inner_.base(); }
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  constexpr V base() && { return std::move(inner_).base(); }
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  constexpr auto begin() {
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  return iterator<false>(*this, inner_.begin());
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  }
 
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  }
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  constexpr auto size() const requires sized_range<const InnerView> {
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  return inner_.size();
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  }
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+
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+ constexpr auto reserve_hint() requires approximately_sized_range<InnerView> {
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+ return inner_.reserve_hint();
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+ }
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+
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+ constexpr auto reserve_hint() const requires approximately_sized_range<const InnerView> {
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+ return inner_.reserve_hint();
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+ }
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  };
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  }
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  ```
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  ``` cpp
 
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  constexpr iterator(Parent& parent, inner-iterator<Const> inner); // exposition only
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  public:
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  using iterator_category = see below;
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+ using iterator_concept = inner-iterator<Const>::iterator_concept;
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  using value_type =
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  remove_cvref_t<invoke_result_t<maybe-const<Const, F>&,
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  REPEAT(range_reference_t<Base>, N)...>>;
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  using difference_type = range_difference_t<Base>;
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  template<bool OtherConst>
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  requires sentinel_for<inner-sentinel<Const>, inner-iterator<OtherConst>>
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  friend constexpr bool operator==(const iterator<OtherConst>& x, const sentinel& y);
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  ```
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+ *Effects:* Equivalent to: `return x.`*`inner_`*` == y.`*`inner_`*`;`
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  ``` cpp
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  template<bool OtherConst>
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  requires sized_sentinel_for<inner-sentinel<Const>, inner-iterator<OtherConst>>
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  friend constexpr range_difference_t<maybe-const<OtherConst, InnerView>>
 
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  requires sized_sentinel_for<inner-sentinel<Const>, inner-iterator<OtherConst>>
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  friend constexpr range_difference_t<maybe-const<OtherConst, InnerView>>
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  operator-(const sentinel& x, const iterator<OtherConst>& y);
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  ```
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+ *Effects:* Equivalent to: `return x.`*`inner_`*` - y.`*`inner_`*`;`
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