The main takeaway here is that Haskell's stream fusion library is very nice. You can write code in the "naive" modular style that generates intermediate lists,

The main takeaway here is that Haskell's stream fusion library is very nice. You can write code in the "naive" modular style that generates intermediate lists, and they get automagically fused away. There's a little work on that in Lispland as well. Some discussion, a prototype, and a link to the older SERIES package: http://pvk.ca/Blog/Lisp/Pipes/ http://pvk.ca/Blog/Lisp/Pipes/