[klodolph]

> I suspect these programs have a larger essential "hairiness." grep only has to search text. But Find in a text editor has to show a progress bar, cancel button, intermediate result count, etc. These features are intimately intertwined with the algorithm itself, and that's often hard in FP. Try writing a Haskell function that does text find/replace with live progress reporting. It's not easy, and it ends up looking a bit like Java.

Ah, I suspect you're not familiar with things like conduits/pipes/iteratees/etc. These allow you to express and compose those kinds of dirty things that you're looking for--incremental input/output, progress reporting, etc. So you could write a text search function, compose it with a progress reporter that reports how quickly it traverses input, and then report the output progressively, and dispose the whole thing at any time. Haskell's type system is fairly awesome at letting you do things like this, enough that people are still discovering neat tricks decades later.