On Tue, Sep 20, 2005 at 04:30:25PM +0100, Neil Mitchell wrote:
Take a look at unsafePerformIO, it is of type IO a -> a. Its not particularly "safe" (the name gives a clue), but it does what you want.
I dont think you would ever need to do unsafePerformIO unless you are writing some lib calls or some such thing
onMouse w streams isEditChecked mouse = case mouse of MouseLeftDown pt mods -> if isEditChecked then findStream w streams pt else addStream w streams pt other -> skipCurrentEvent --
In your case the approach should be some thing along these lines onMouse w streams isEditChecked mouse = do ischecked <- isEditChecked case mouse of if ischecked then findStream w streams pt ... I am assuming that findStream w streams pt is of type IO a for some a. otherwise you might have to use something like return $ findStream w streams pt Also the function onMouse will return some IO something. Remember there is no real reason to use unsafePerformIO unless you are writing some new IO library call. ppk