NAME¶

std::experimental::ranges::Swappable,std::experimental::ranges::SwappableWith - std::experimental::ranges::Swappable,std::experimental::ranges::SwappableWith

Synopsis¶

Defined in header <experimental/ranges/concepts>
template< class T >

concept bool Swappable =
requires(T& a, T& b) { (1) (ranges TS)
ranges::swap(a, b);

};
template< class T, class U >

concept bool SwappableWith =
CommonReference<
const std::remove_reference_t<T>&,
const std::remove_reference_t<U>&> &&
requires(T&& t, U&& u) { (2) (ranges TS)
ranges::swap(std::forward<T>(t), std::forward<T>(t));
ranges::swap(std::forward<U>(u), std::forward<U>(u));
ranges::swap(std::forward<T>(t), std::forward<U>(u));
ranges::swap(std::forward<U>(u), std::forward<T>(t));

};

The concept Swappable<T> specifies that lvalues of type T are swappable.

The concept SwappableWith<T, U> specifies that expressions of the type and value
category encoded by T and U are swappable with each other. SwappableWith<T, U> is
satisfied only if a call to ranges::swap(t, u) exchanges the value of t and u, that
is, given distinct objects t2 equal to t and u2 equal to u, after evaluating either
ranges::swap(t, u) or ranges::swap(u, t), t2 is equal to u and u2 is equal to t.

Equality preservation

An expression is equality preserving if it results in equal outputs given equal
inputs.

* The inputs to an expression consist of its operands.
* The outputs of an expression consist of its result and all operands modified by
the expression (if any).

Every expression required to be equality preserving is further required to be
stable: two evaluations of such an expression with the same input objects must have
equal outputs absent any explicit intervening modification of those input objects.

Unless noted otherwise, every expression used in a requires-expression is required
to be equality preserving and stable, and the evaluation of the expression may only
modify its non-constant operands. Operands that are constant must not be modified.