std::experimental::ranges::Relation
<experimental/ranges/concepts>
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> &&
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))).