Agreed that, in some senses, I was trying to force a square peg into a round hole, but the comments on my blog suggest that others share my experience and they'

Agreed that, in some senses, I was trying to force a square peg into a round hole, but the comments on my blog suggest that others share my experience and they're mostly from planet.haskell.org. So I think something is missed if my experience is entirely chalked up to ignorance. My post was written fairly quickly and got more attention than I expected. Looking at it again and looking at Turbinado's code, I can see how you could suggest that I don't understand monads. And I probably don't understand them to your level, but the code reflects the result of trying to compose together a number of libraries into a sensible system. Wrapping those libraries in composed monad transformers was vastly more complicated than just dropping down to the IO monad, so I stripped down... w.r.t monads: they're lovely for constraining code behavior and for building DSLs, so other languages have added monad libraries. They haven't forced the entire language to live within monads... w.r.t incremental data structures: I mentioned in my post that I wasn't happy with multiple data types. Multiple constructors sound even less productive. Currying is a solid suggestion. - Alson