fsnotify.hs

import System.FSNotify
import Control.Concurrent (threadDelay)
import Control.Monad (forever)

main =
  withManager $ \mgr -> do
    -- start a watching job (in the background)
    watchDir
      mgr          -- manager
      "."          -- directory to watch
      (const True) -- predicate
      print        -- action

    -- sleep forever (until interrupted)
    forever $ threadDelay 1000000

gloss.hs

import Graphics.Gloss

windowDisplay :: Display
windowDisplay = InWindow "Window" (200, 200) (10, 10)

main :: IO ()
main = animate windowDisplay white animationFunc

animationFunc :: Float -> Picture
animationFunc time = Circle (1 * time)