Have you tried functional programming, yet? John Hughes argues in "Why functional programming matters" (http://www.cse.chalmers.se/~rjmh/Papers/whyfp.html) that enabling exactly this separation and subsequent gluing together is exactly what makes FP worth looking at.
Yep. The very example I was talking about was written in Ocaml. It was in an earlier version of my web site compiler: http://loup-vaillant.fr/projects/ussm/
I liked Hughes paper. Funnily enough, the lack of laziness in Ocaml quite hindered me when I wrote and used my Parsec clone (again in USSM, but in the current version).
