Ticket #4460: Main.hs

module Main (main) where

import Control.Monad
import Control.Monad.Trans
import System.Console.Haskeline as Haskeline
import System.IO

main :: IO ()
main = do
    hSetBuffering stdout NoBuffering
    hFlush stdout
    hSetBuffering stdout NoBuffering
    hSetBuffering stdin NoBuffering
    runInputT defaultSettings runCommands
    putStrLn "Leaving."

nextInputLine :: InputT IO (Maybe String)
nextInputLine = getInputLine "Prompt: "

runCommands :: InputT IO ()
runCommands = do
    b <- runOneCommand
    unless b $ runCommands

runOneCommand :: InputT IO Bool
runOneCommand = do
  mb_cmd <- nextInputLine
  case mb_cmd of
    Nothing -> return True
    Just c  -> do liftIO $ print ('C', c)
                  return False