Steven Huwig wrote: [...]
1) Did I miss something in the Prelude or standard library that gives me this functionality, or something close to it?
[...]
3) The 3-tuple output of unravel looks ugly to me, but I can't think of an alternative. For the case where there is an equal number of p-groups and not-p-groups, we need to know which side to start the zipWith. Does anyone have a better way?
Here's another way to get something similar. import Data.Char(isSpace) import Data.List(groupBy) (op `on` f) x y = f x `op` f y wordsAndSpaces = groupBy ((==) `on` isSpace) It has a couple of advantages: laziness, and being reversible by good ol' concat. It's a slight nuisance that you have to use isSpace *again* to get your bearings, if you use wordsAndSpaces in a mapWords function. Regards, Tom