24 Ranges library [ranges]

24.7 Range adaptors [range.adaptors]

24.7.1 General [range.adaptors.general]

Subclause [range.adaptors] defines range adaptors, which are utilities that transform a range into a view with custom behaviors.
These adaptors can be chained to create pipelines of range transformations that evaluate lazily as the resulting view is iterated.
Range adaptors are declared in namespace std​::​ranges​::​views.
The bitwise OR operator is overloaded for the purpose of creating adaptor chain pipelines.
The adaptors also support function call syntax with equivalent semantics.
[Example 1: vector<int> ints{0,1,2,3,4,5}; auto even = [](int i) { return 0 == i % 2; }; auto square = [](int i) { return i * i; }; for (int i : ints | views::filter(even) | views::transform(square)) { cout << i << ' '; // prints: 0 4 16 } assert(ranges::equal(ints | views::filter(even), views::filter(ints, even))); — end example]