25 Ranges library [ranges]

adjacent_view takes a view and produces a view whose $M^{\text{th}}$ element is a tuple of references to the $M^{\text{th}}$ through $(M+N-1{)}^{\text{th}}$ elements of the original view.

If the original view has fewer than N elements, the resulting view is empty.

The name views​::​adjacent<N> denotes a range adaptor object ([range.adaptor.object]).

Given a subexpression E and a constant expression N, the expression views​::​adjacent<N>(E) is expression-equivalent to

• (2.1)
  ((void)E, auto(views​::​empty<tuple<>>)) if N is equal to 0 and decltype((E)) models forward_range,
• (2.2)
  otherwise, adjacent_view<views​::​all_t<decltype((E))>, N>(E).

Define REPEAT(T, N) as a pack of N types, each of which denotes the same type as T.