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Section: 18.104.22.168 [range.iota.view] Status: WP Submitter: Jiang An Opened: 2021-09-29 Last modified: 2022-02-10
Priority: Not Prioritized
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It seems that the iota_view tends to accept integer-class types as its value types, by using is-integer-like or is-signed-integer-like through the specification, although it's unspecified whether any of them satisfies weakly_incrementable. However, the requires-clause of iota_view::size (22.214.171.124 [range.iota.view] p16) uses (integral<W> && integral<Bound>), which sometimes rejects integer-class types.Should we relax the restrictions by changing this part to (is-integer-like<W> && is-integer-like<Bound>)?
[2021-10-14; Reflector poll]
Set status to Tentatively Ready after six votes in favour during reflector poll.
[2022-02-10 Approved at February 2022 virtual plenary. Status changed: Tentatively Ready → WP.]
This wording is relative to N4892.
Modify 126.96.36.199 [range.iota.view] as indicated:
constexpr auto size() const requires see below;
-15- Effects: Equivalent to:if constexpr (is-integer-like<W> && is-integer-like<Bound>) return (value_ < 0) ? ((bound_ < 0) ? to-unsigned-like(-value_) - to-unsigned-like(-bound_) : to-unsigned-like(bound_) + to-unsigned-like(-value_)) : to-unsigned-like(bound_) - to-unsigned-like(value_); else return to-unsigned-like(bound_ - value_);
-16- Remarks: The expression in the requires-clause is equivalent to:(same_as<W, Bound> && advanceable<W>) || (
integral<W> && integral<Bound>) || sized_sentinel_for<Bound, W>