Haskell-book/13/Palindrome.hs


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module Palindrome where

import Control.Monad
import Data.Char
import System.Exit

format :: String -> String
format s = filter (\x -> x >= 'a' && x <= 'z') (map toLower s)

palindrome :: IO ()
palindrome = forever $ do
    line1 <- getLine
    case ((format line1) == (format $ reverse line1)) of
      True -> putStrLn "It's a palindrome!"
      False -> do
          putStrLn "Nope!"
          exitSuccess

main :: IO ()
main = palindrome