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Implement LWG-4035 single_view should provide empty #4525

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Merged
Stephan T. Lavavej (StephanTLavavej) merged 3 commits into from
Mar 28, 2024
Merged

Implement LWG-4035 single_view should provide empty #4525

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2e4f38b
Add empty to single_view
grcm10 Mar 24, 2024
6373ccd
Fix the formatting error
grcm10 Mar 24, 2024
93d7299
Follow the Standard's declaration order.
StephanTLavavej Mar 25, 2024
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4 changes: 4 additions & 0 deletions stl/inc/ranges
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Original file line number Diff line number Diff line change
Expand Up @@ -1031,6 +1031,10 @@ namespace ranges {
return data() + 1;
}

_NODISCARD static constexpr bool empty() noexcept {
return false;
}

_NODISCARD static constexpr size_t size() noexcept {
return 1;
}
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7 changes: 7 additions & 0 deletions tests/std/tests/P0896R4_views_single/test.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -52,6 +52,13 @@ constexpr bool test_one_type(T value, Args&&... args) {
same_as<R> auto r0 = ranges::single_view{value};
const R& cr0 = r0;

// validate member empty
static_assert(same_as<decltype(R::empty()), bool>);
static_assert(R::empty() == false);
static_assert(noexcept(R::empty()));
static_assert(noexcept(ranges::empty(r0)));
static_assert(noexcept(ranges::empty(cr0)));

// validate member size
static_assert(same_as<decltype(R::size()), size_t>);
static_assert(R::size() == 1);
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