Hi Emmanuel, you could write monadic boolean operators (<&&>, <||>) and a "monadic" when (whenM) - I think both are in some package - to be able to write somwthing like: whenM (not <$> doesFileExist file <||> olderThan twoHours file) $ do ... import Control.Applicative ((<$>)) (<&&>) :: Monad m => m Bool -> m Bool -> m Bool (<&&>) m1 m2 = do r1 <- m1 if r1 then m2 else return False (<||>) :: Monad m => m Bool -> m Bool -> m Bool (<||>) m1 m2 = do r1 <- m1 if r1 then return True else m2 whenM :: Monad m => m Bool -> m () -> m () whenM p m = do r <- p if r then m else return () olderThan :: Int -> FilePath -> IO Bool olderThan secs file = do modif <- getModificationTime file curTime <- getClockTime let diff = diffClockTimes curTime modif return $ tdSec diff >= secs twoHours = 3600 * 2 'not <$> doesFileExist file' is a shorcut for: r <- doesFileExist file return $ not r But all of this would mostly only really pay off, if you have some file operations heavy code. Otherwise, all of these helper functions (operators) are quite generic. Obviously, I'm currently a bit bored ... Greetings, Daniel