main = do args <- getArgs
          case length args of
            0 -> runRepl
            1 -> runOne $ args !! 0
            otherwise -> putStrLn "Program takes only 0 or 1 argument"
main = do args <- getArgs
          case length args of
            0 -> runRepl
            1 -> runOne $ args !! 0
            otherwise -> putStrLn "Program takes only 0 or 1 argument"
main = do args <- getArgs
          case length args of
            0 -> runRepl
            1 -> runOne $ args !! 0
            otherwise -> putStrLn "Program takes only 0 or 1 argument"