[Haskell-beginners] example of compostion

[Rainer Grimm]

Hello,
I'm looking for a good example of function composition. It's very
impressive, how concise you can extract information out of a file in
Haskell. So I write a short programm, which gets all title words out of
a given file sorted by their length.
How could the following programm be improved?


import Data.Char (isUpper,isLower)
import Data.List (sortBy)
import Data.Ord (comparing)

isTitle word=  
  isFirstUpperCase ( word) && isTailLowerCase ( word )
  where isFirstUpperCase= isUpper . head
    isTailLowerCase= all isLower . tail

main = do
  putStrLn "The name of the input file:"
  file <- getLine
  inputString <- readFile file
  let allTitles= reverse . sortBy (comparing length ) . filter isTitle $
words inputString
  putStrLn $ show $ take 15  allTitles
  putStrLn $ show (length allTitles) ++ " titles in " ++ file


Thanks in advance,
Rainer

-- 
Rainer Grimm  rainer at grimm-jaud.de
              http://www.grimm-jaud.de


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