I don’t understand why the above got down-voted... Without fusing (lazy) loops, having a bunch of independent sequential transformations (each with its own loop) can make the same computation significantly slower!
Yeah, you can emulate laziness at the library level with iterators, coroutines and whatnot, but it always comes with a certain API friction (some readers might be familiar with the “colored functions” analogy [1]) compared to Haskell’s approach that takes laziness to the extreme.
I was really hoping that article was going to start talking about effect systems. They're so cool! They make it possible to have many different function colors without it being a huge chore. They can be thought of as a more-ergonomic generalization of monads.