std::ranges::viewable_range - cppreference.com (original) (raw)

The viewable_range concept is a refinement of range that describes a range that can be converted into a view through views::all.

The constant /*is-initializer-list*/<T> is true if and only if std::remove_cvref_t<T> is a specialization of std::initializer_list.

[edit] Example

#include #include #include   struct valid_result {}; struct invalid_result {};   template concept valid_viewable_range = std::same_as<T, valid_result>;   template concept invalid_viewable_range = std::same_as<T, invalid_result>;   auto test_viewable_range(std::ranges::viewable_range auto &&) -> valid_result; auto test_viewable_range(auto&&) -> invalid_result;   int main() { auto il = {1, 2, 3}; int arr []{1, 2, 3}; std::vector vec{1, 2, 3}; std::ranges::ref_view r{arr}; std::ranges::owning_view o{std::string("Hello")};   static_assert(requires { { test_viewable_range(il) } -> valid_viewable_range; { test_viewable_range(std::move(il)) } -> invalid_viewable_range; { test_viewable_range(arr) } -> valid_viewable_range; { test_viewable_range(std::move(arr)) } -> invalid_viewable_range; { test_viewable_range(vec) } -> valid_viewable_range; { test_viewable_range(std::move(vec)) } -> valid_viewable_range; { test_viewable_range(r) } -> valid_viewable_range; { test_viewable_range(std::move(r)) } -> valid_viewable_range; { test_viewable_range(o) } -> invalid_viewable_range; { test_viewable_range(std::move(o)) } -> valid_viewable_range; { test_viewable_range(std::ranges::ref_view(o)) } -> valid_viewable_range; }); }

[edit] Defect reports

The following behavior-changing defect reports were applied retroactively to previously published C++ standards.

[edit] See also