[range.utility.conv.general] (original) (raw)

25 Ranges library [ranges]

25.5 Range utilities [range.utility]

25.5.7 Range conversions [range.utility.conv]

25.5.7.1 General [range.utility.conv.general]

The range conversion functions construct an object (usually a container) from a range, by using a constructor taking a range, a from_range_t tagged constructor, or a constructor taking a pair of iterators, or by inserting each element of the range into the default-constructed object.

ranges​::​to is applied recursively, allowing the conversion of a range of ranges.

[Example 1: string_view str = "the quick brown fox";auto words = views::split(str, ' ') | to<vector<string>>(); — _end example_]

Let reservable-container be defined as follows:template<class Container> constexpr bool reservable-container = sized_range<Container> && requires(Container& c, range_size_t<Container> n) { c.reserve(n);{ c.capacity() } -> same_as<decltype(n)>;{ c.max_size() } -> same_as<decltype(n)>;};

Let container-appendable be defined as follows:template<class Container, class Ref> constexpr bool container-appendable = requires(Container& c, Ref&& ref) { requires (requires { c.emplace_back(std::forward<Ref>(ref)); } || requires { c.push_back(std::forward<Ref>(ref)); } || requires { c.emplace(c.end(), std::forward<Ref>(ref)); } || requires { c.insert(c.end(), std::forward<Ref>(ref)); });};

Let container-append be defined as follows:template<class Container> constexpr auto container-append(Container& c) { return [&c]<class Ref>(Ref&& ref) { if constexpr (requires { c.emplace_back(declval<Ref>()); }) c.emplace_back(std::forward<Ref>(ref));else if constexpr (requires { c.push_back(declval<Ref>()); }) c.push_back(std::forward<Ref>(ref));else if constexpr (requires { c.emplace(c.end(), declval<Ref>()); }) c.emplace(c.end(), std::forward<Ref>(ref));else c.insert(c.end(), std::forward<Ref>(ref));};}