A wordcount program in Haskell as an example of programming as data transformation

Wordcount.hs

import qualified Data.Map as M
import Control.Arrow ((>>>))
import Data.List (intercalate)
import GHC.Exts (sortWith)

main = interact $ words 
              >>> foldr incr M.empty
              >>> M.toList
              >>> sortWith (negate . snd)
              >>> map show
              >>> intercalate "\n"
    where incr k = M.insertWith' (+) k 1