lined.hs

-- foo.txtを読み込んで行番号をつけて表示
-- ※同ディレクトリにApplicativeParsec.hsが要る
import ApplicativeParsec

p :: CharParser () [PLine]
p = many line

eol = string "\n"

letters = many1 letter

data PLine = PLine Int String deriving Eq

instance Show PLine where
  show (PLine i str) = (show i) ++ ": " ++ str

line :: CharParser () PLine
line = do
  i <- getPosition
  str <- letters
  eol
  return $ PLine (sourceLine i) str

main = do
  cs <- readFile "foo.txt"
  case parse p "(stdin)" cs of
       Left e -> do putStrLn "Error parsing input:"
                    print e
       Right r -> mapM_ (putStrLn.show) r