path: root/Utils.hs

{-
 - Copyright 2015 Egor Tensin <Egor.Tensin@gmail.com>
 - This file is licensed under the terms of the MIT License.
 - See LICENSE.txt for details.
-}

module Utils where

import Control.Monad ( liftM )
import Data.Char ( toLower )
import System.IO ( hFlush, stdout )

prompt :: String -> IO String
prompt banner = do
  putStr banner
  hFlush stdout
  getLine

promptYesNo :: String -> IO Bool
promptYesNo banner = do
  response <- liftM (map toLower) $ prompt banner
  if response `elem` yeses
    then return True
    else if response `elem` noes
      then return False
      else promptToContinue
  where
    yeses = ["y", "yes"]
    noes = ["n", "no"]

promptToContinue :: IO Bool
promptToContinue = promptYesNo "Continue? (y/n) "