Fiddlosopher.hs

module Main where

import qualified Data.ByteString.Char8 as B
import Data.Char (chr,ord)

isSpace ∷ Char → Bool
isSpace ' '  = True
isSpace '\t' = True
isSpace '\n' = True
isSpace '\r' = True
isSpace _    = False

toUpper ∷ Char → Char
toUpper x
   | (x >= 'a' && x <= 'z') = chr $ ord x - 32
   | otherwise = x

fun ∷ Char → Char → Char
fun a b | isSpace a = toUpper b
        | otherwise = b

convert ∷ B.ByteString → B.ByteString
convert = B.tail . B.scanl fun ' '

main ∷ IO ()
main = B.readFile "input.txt" >>= B.putStr . convert

Fiddlosopher2.hs

module Main where

import Data.Char (chr,ord)
import Foreign.C.Types (CInt(..))
import qualified Data.ByteString.Char8 as B

foreign import ccall unsafe "u_iswspace"
   iswspace ∷ CInt → CInt

isSpace ∷ Char → Bool
{-# INLINE isSpace #-}
isSpace c
   | c > '\x20' && c < '\xa0' = False
   | c == ' '                 = True
   | '\t' <= c && c <= '\r'   = True
   | c == '\xa0'              = True
   | otherwise                = iswspace (fromIntegral (ord c)) /= 0

toUpper ∷ Char → Char
toUpper x
   | (x >= 'a' && x <= 'z') = chr $ ord x - 32
   | otherwise = x

fun ∷ Char → Char → Char
fun a b | isSpace a = toUpper b
        | otherwise = b

convert ∷ B.ByteString → B.ByteString
convert = B.tail . B.scanl fun ' '

main ∷ IO ()
main = B.readFile "input.txt" >>= B.putStr . convert

Fiddlosopher3.hs

module Main where

import Data.Char (chr,ord)
import Foreign.C.Types (CInt(..))
import qualified Data.ByteString.Char8 as B

foreign import ccall unsafe "u_iswspace"
   iswspace ∷ CInt → CInt

isSpace ∷ Char → Bool
{-# INLINE isSpace #-}
isSpace c
   | c > '\x20' && c < '\xa0' = False
   | c == ' '                 = True
   | '\t' <= c && c <= '\r'   = True
   | c == '\xa0'              = True
   | otherwise                = iswspace (fromIntegral (ord c)) /= 0

toUpper ∷ Char → Char
toUpper x
   | (x >= 'a' && x <= 'z') = chr $ ord x - 32
   | otherwise = x

fun ∷ Char → Char → Char
fun a b | isSpace a = toUpper b
        | otherwise = b

op ∷ Bool → Char → (Bool, Char)
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