gistfile1.hs

module Main where

import Data.Word8 (Word8, _cr, _space, _tab, isAsciiLower)
import qualified Data.ByteString as B

isSpace ∷ Word8 → Bool
isSpace w = w == _space || w <= _cr && w >= _tab

toUpper ∷ Word8 → Word8
toUpper w = if isAsciiLower w then w - _space else w

op ∷ Bool → Word8 → (Bool, Word8)
op flag c = if isSpace c then (True,c) else (False,d)
   where d = if flag then toUpper c else c

main ∷ IO ()
main = B.readFile "input.txt" >>= B.putStr . snd . B.mapAccumL op True