LinqBegin60 (from PT4) on Haskell

LinqBegin60.hs

import Data.List
import Data.Ord (comparing)
import Data.Char (ord)
import Control.Applicative ((<$>))

equating f = \a b -> f a == f b

thenBy ord' = concat
    . map (sortBy ord')
    . groupBy (equating length)

myPrint s = (show $ length s) ++ "-" ++  [head s]

main = map myPrint
    . thenBy (comparing (ord . head))
    . sortBy (flip $ comparing length)
    . map concat
    . groupBy (equating head)
    . sort
    . lines
    <$> test -- getContents -- for stdin

test :: IO String
test = return $
        intercalate "\n"
        ["GRPWB", "LNKF",  "CBF",   "D",
         "IABW",  "IAJDY", "H",     "PBGNI",
         "F",     "G",     "CRXC",  "OYVFW"]