25 Ranges library [ranges]

25.7 Range adaptors [range.adaptors]

25.7.26 Zip transform view [range.zip.transform]

25.7.26.1 Overview [range.zip.transform.overview]

zip_transform_view takes an invocable object and any number of views and produces a view whose

M^{th}

element is the result of applying the invocable object to the

M^{th}

elements of all views.

The name views::zip_transform denotes a customization point object ([customization.point.object]).

Let F be a subexpression, and let Es... be a pack of subexpressions.

(2.1)
If Es is an empty pack, let FD be decay_t<decltype((F))>.
- (2.1.1)
  If move_constructible<FD> && regular_invocable<FD&> is false, or if decay_t<invoke_result_t<FD&>> is not an object type, views::zip_transform(F, Es...) is ill-formed.
- (2.1.2)
  Otherwise, the expression views::zip_transform(F, Es...) is expression-equivalent to ((void)F, auto(views::empty<decay_t<invoke_result_t<FD&>>>))
(2.2)
Otherwise, the expression views::zip_transform(F, Es...) is expression-equivalent to zip_transform_view(F, Es...).

[Example 1: vector v1 = {1, 2}; vector v2 = {4, 5, 6}; for (auto i : views::zip_transform(plus(), v1, v2)) { cout << i << ' '; // prints 5 7 } — end example]