C++26 Ranges: Four New Views

C++20 shipped a powerful ranges library, but the set of view adaptors had some obvious gaps. Want to get the output as a container? No luck. At least C++23 helped with that. Want to iterate over two vectors as one sequence? Write your own. Want to avoid redundant evaluations in a transform | filter pipeline? Write a workaround. Want a quick index sequence matching a range’s size? Spell out iota...