who are you?

who.hs

module Main where
 
import qualified Data.Map as M
 
errorsPerLine = M.fromList
    [ ("Chris", 472), ("Don", 100), ("Simon", -5) ]
 
main = do putStrLn "Who are you?"
          name <- getLine
          case M.lookup name errorsPerLine of
              Nothing -> putStrLn "I don't know you"
              Just n  -> do putStr "Errors per line: "
                            print n