[GUI] Haskell extention and Implementing Callbacks with a list

Hello, I've got two Ideas: 1) Add a haskell extention (wouldn't this be possible?) that allows for equality for functions. Maybe only valid for IO() functions. Say we have: a :: IO () We know that (a == a) but a doesn't equal anything else. This would make the unregister process much neater. 2) Would it not be possible to do callbacks with lists? button [ onClick := [messageBox "hi there"] ] add a callback: set myButton [ onClick :~ (/a -> newFunction:a) ] And if the onClick function found it had an empty list, it would unregister the callback with the underlying library. David J. Sankel