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std::ranges::views::as_rvalue, std::ranges::as_rvalue_view

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< cpp‎ | ranges
 
 
Ranges library
Range access
Range conversions
(C++23)

Range primitives



Dangling iterator handling
Range concepts
Views

Range factories
Range adaptors
Range generators
Range adaptor objects
Range adaptor closure objects
Helper items
(until C++23)(C++23)


 
Defined in header <ranges>
template< ranges::view V >

    requires ranges::input_range<V>
class as_rvalue_view

    : public ranges::view_interface<as_rvalue_view<V>>
(1) (since C++23)
namespace views {

    inline constexpr /* unspecified */ as_rvalue = /* unspecified */;

}
(2) (since C++23)
Call signature
template< ranges::viewable_range R >

    requires /* see below */

constexpr ranges::view auto as_rvalue( R&& r );
(since C++23)
1) A range adaptor that represents a view of underlying view whose elements are rvalues.
2) RangeAdaptorObject. Let e be a subexpression and let T be decltype((e)). Then the expression views::as_rvalue(e) is expression-equivalent to:

Contents

[edit] Data members

Member object Definition
base_ (private) The underlying view of type V.
(exposition-only member object*)

[edit] Member functions

constructs an as_rvalue_view
(public member function)
returns the underlying view V
(public member function)
returns the beginning iterator of the as_rvalue_view
(public member function)
returns the end iterator of the as_rvalue_view
(public member function)
returns the size of the view if it is bounded
(public member function)
Inherited from std::ranges::view_interface
(C++20)
returns whether the derived view is empty. Provided if it satisfies sized_range or forward_range.
(public member function of std::ranges::view_interface<D>) [edit]
(C++23)
returns a constant iterator to the beginning of the range.
(public member function of std::ranges::view_interface<D>) [edit]
(C++23)
returns a sentinel for the constant iterator of the range.
(public member function of std::ranges::view_interface<D>) [edit]
returns whether the derived view is not empty. Provided if ranges::empty is applicable to it.
(public member function of std::ranges::view_interface<D>) [edit]
(C++20)
returns the first element in the derived view. Provided if it satisfies forward_range.
(public member function of std::ranges::view_interface<D>) [edit]
(C++20)
returns the last element in the derived view. Provided if it satisfies bidirectional_range and common_range.
(public member function of std::ranges::view_interface<D>) [edit]
returns the nth element in the derived view. Provided if it satisfies random_access_range.
(public member function of std::ranges::view_interface<D>) [edit]

std::ranges::as_rvalue_view::as_rvalue_view

as_rvalue_view() requires std::default_initializable<V> = default;
(1) (since C++23)
constexpr explicit as_rvalue_view( V base );
(2) (since C++23)
1) Value-initializes base_ via its default member initializer (= V()).
2) Initializes base_ with std::move(base).

Parameters

base - a view

std::ranges::as_rvalue_view::base

constexpr V base() const& requires std::copy_constructible<V>;
(1) (since C++23)
constexpr V base() &&;
(2) (since C++23)

Returns the underlying view.

1) Copy-constructs the result from the underlying view. Equivalent to return base_;.
2) Move-constructs the result from the underlying view. Equivalent to return std::move(base_);.

std::ranges::as_rvalue_view::begin

constexpr auto begin() requires (!__simple_view<V>);
(1) (since C++23)
constexpr auto begin() const requires ranges::range<const V>;
(2) (since C++23)
1,2) Returns std::move_iterator(ranges::begin(base_)).

std::ranges::as_rvalue_view::end

constexpr auto end() requires (!__simple_view<V>);
(1) (since C++23)
constexpr auto end() const requires ranges::range<const V>;
(2) (since C++23)
1) Returns std::move_iterator(ranges::end(base_)) if V models common_range, otherwise std::move_sentinel(ranges::end(base_)).
2) Returns std::move_iterator(ranges::end(base_)) if const V models common_range, otherwise std::move_sentinel(ranges::end(base_)).

std::ranges::as_rvalue_view::size

constexpr auto size() requires ranges::sized_range<V>;
(1) (since C++23)
constexpr auto size() const requires ranges::sized_range<const V>;
(2) (since C++23)

Returns the size of the view if the view is bounded.

1,2) Equivalent to return ranges::size(base_);

[edit] Deduction guides

template< class R >
as_rvalue_view( R&& ) -> as_rvalue_view<views::all_t<R>>;
(since C++23)

[edit] Helper templates

template< class T >

inline constexpr bool enable_borrowed_range<std::ranges::as_rvalue_view<T>> =

    std::ranges::enable_borrowed_range<T>;
(since C++23)

This specialization of std::ranges::enable_borrowed_range makes as_rvalue_view satisfy borrowed_range when the underlying view satisfies it.

[edit] Notes

Feature-test macro Value Std Feature
__cpp_lib_ranges_as_rvalue 202207L (C++23) std::ranges::as_rvalue_view

[edit] Example

[edit] See also

iterator adaptor which dereferences to an rvalue
(class template) [edit]
sentinel adaptor for use with std::move_iterator
(class template) [edit]
converts a view into a constant_range
(class template) (range adaptor object)[edit]