std::experimental::ranges::Relation

 

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Defined in header <experimental/ranges/concepts>
template< class R, class T, class U > concept bool Relation = Predicate<R, T, T> && Predicate<R, U, U> && CommonReference< const std::remove_reference_t<T>&, const std::remove_reference_t<U>&> && Predicate<R, ranges::common_reference_t< const std::remove_reference_t<T>&, const std::remove_reference_t<U>&>, ranges::common_reference_t< const std::remove_reference_t<T>&, const std::remove_reference_t<U>&>> && Predicate<R, T, U> && Predicate<R, U, T>;	(1)	(ranges TS)

The concept Relation<R, T, U> specifies that R defines a binary relation over the set of expressions whose type and value category are those encoded by either T or U.

Given

• r, an expression such that decltype((r)) is R,
• t, an expression such that decltype((t)) is T,
• u, an expression such that decltype((u)) is U,

and let C be ranges::common_reference_t<const std::remove_reference_t<T>&, const std::remove_reference_t<U>&>,

then Relation<R, T, U> is satisfied only if

• bool(r(t, u)) == bool(r(C(t), C(u))) and
• bool(r(u, t)) == bool(r(C(u), C(t))).