The function is: om f m = (m >>=) . flip f Allowing this typical usage: om when (return True) $ print "Hello" Thus, it allows one to do away with the monadic variants of pure functions, such as "whenM", "unlessM", etc.: whenM = om when unlessM = om unless "om" gets even more handy when you want to apply a monadic function to a monadic value in yet another monad: >>> om for_ (return (Just True)) print True Rather than the typical (which I must have written hundreds of times by now): mx <- return (Just x) for_ mx $ \x -> {- use x... -} A rider to this proposal is to also add "nom = flip om", but I can live without that one. "om", however, is handy enough that I've started locally defining in all the modules where I find myself now reaching for it. -- John Wiegley FP Complete Haskell tools, training and consulting http://fpcomplete.com johnw on #haskell/irc.freenode.net