Beautiful folding> {-# LANGUAGE ExistentialQuantification #-} > import Data.List (foldl') If you're not a Haskeller, and were thus hoping to learn how to fold a shirt beautifully, I'm afraid you're out of luck. I don't know either. Much has been said about writing a Haskell function to calculate the mean of a list of numbers. For example, see Don Stewart's "Write Haskell as fast as C". Basically, one wants to writ
