C++ named requirements: LayoutMapping (since C++23)

Since C++23

LayoutMapping controls the mapping of a multidimensional index to a one-dimensional offset to data handle in std::mdspan.

# Declarations

template< class M >
concept /*layout-mapping-alike*/ = requires
{
requires /*is-extents*/<typename M::extents_type>;
{ M::is_always_strided() } -> std::same_as<bool>;
{ M::is_always_exhaustive() } -> std::same_as<bool>;
{ M::is_always_unique() } -> std::same_as<bool>;
std::bool_constant<M::is_always_strided()>::value;
std::bool_constant<M::is_always_exhaustive()>::value;
std::bool_constant<M::is_always_unique()>::value;
};

(exposition only*)

# See also

LayoutMappingPolicy