std::experimental::ranges::Relation
Defined in header <experimental/ranges/concepts>
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template <class R, class T, class U> concept bool Relation = |
(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)) isR
, -
t
, an expression such that decltype((t)) isT
, -
u
, an expression such that decltype((u)) isU
,
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))).