From Jason Turner

[range.prim.size]

C++20 → C++23 2.4 KB 32 lines
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Archived: C++20 | C++23
Markdown: C++20 | C++23
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  1. tmp/tmpcis9zrz9/{from.md → to.md} +11 -18
tmp/tmpcis9zrz9/{from.md → to.md} RENAMED
@@ -4,31 +4,24 @@ The name `ranges::size` denotes a customization point object
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  [[customization.point.object]].
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  Given a subexpression `E` with type `T`, let `t` be an lvalue that
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  denotes the reified object for `E`. Then:
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- - If `T` is an array of unknown bound [[dcl.array]], `ranges::size(E)`
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- is ill-formed.
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  - Otherwise, if `T` is an array type, `ranges::size(E)` is
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- expression-equivalent to `decay-copy(extent_v<T>)`.
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  - Otherwise, if `disable_sized_range<remove_cv_t<T>>` [[range.sized]] is
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- `false` and `decay-copy(t.size())` is a valid expression of
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- integer-like type [[iterator.concept.winc]], `ranges::size(E)` is
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- expression-equivalent to `decay-copy(t.size())`.
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  - Otherwise, if `T` is a class or enumeration type,
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- `disable_sized_range<remove_cv_t<T>>` is `false` and
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- `decay-copy(size(t))` is a valid expression of integer-like type with
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- overload resolution performed in a context in which unqualified lookup
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- for `size` finds only the declarations
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- ``` cpp
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- void size(auto&) = delete;
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- void size(const auto&) = delete;
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- ```
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-
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- then `ranges::size(E)` is expression-equivalent to
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- `decay-copy(size(t))` with overload resolution performed in the above
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- context.
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  - Otherwise, if `to-unsigned-like(ranges::end(t) - ranges::begin(t))`
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  [[ranges.syn]] is a valid expression and the types `I` and `S` of
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  `ranges::begin(t)` and `ranges::end(t)` (respectively) model both
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  `sized_sentinel_for<S, I>` [[iterator.concept.sizedsentinel]] and
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  `forward_iterator<I>`, then `ranges::size(E)` is expression-equivalent
 
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  [[customization.point.object]].
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  Given a subexpression `E` with type `T`, let `t` be an lvalue that
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  denotes the reified object for `E`. Then:
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+ - If `T` is an array of unknown bound [[term.array.type]],
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+ `ranges::size(E)` is ill-formed.
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  - Otherwise, if `T` is an array type, `ranges::size(E)` is
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+ expression-equivalent to `auto(extent_v<T>)`.
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  - Otherwise, if `disable_sized_range<remove_cv_t<T>>` [[range.sized]] is
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+ `false` and `auto(t.size())` is a valid expression of integer-like
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+ type [[iterator.concept.winc]], `ranges::size(E)` is
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+ expression-equivalent to `auto({}t.size())`.
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  - Otherwise, if `T` is a class or enumeration type,
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+ `disable_sized_range<remove_cv_t<T>>` is `false` and `auto(size(t))`
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+ is a valid expression of integer-like type where the meaning of `size`
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+ is established as-if by performing argument-dependent lookup only
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+ [[basic.lookup.argdep]], then `ranges::size(E)` is
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+ expression-equivalent to that expression.
 
 
 
 
 
 
 
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  - Otherwise, if `to-unsigned-like(ranges::end(t) - ranges::begin(t))`
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  [[ranges.syn]] is a valid expression and the types `I` and `S` of
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  `ranges::begin(t)` and `ranges::end(t)` (respectively) model both
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  `sized_sentinel_for<S, I>` [[iterator.concept.sizedsentinel]] and
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  `forward_iterator<I>`, then `ranges::size(E)` is expression-equivalent