Asyn user input

input.hs

main = do
  hSetBuffering stdin NoBuffering
  hSetEcho stdin False
  mVar <- newMVar "" 
  putStrLn "Go"
  runAfterDelay 1000000 (appender mVar "foo")
  runAfterDelay 2000000 (appender mVar "bar")
  typer mVar
  putStrLn "Main done"

appender mVar x =  
  modifyMVar_ mVar $ \s -> do
   putStrLn (x ++ s)
   return (x ++ s)

typer mVar = do
    c <- getChar
    modifyMVar_ mVar $ \s -> do
      putStrLn (c:s)
      return (c:s)
    if c == 'q' then
      return ()
    else
      typer mVar