At 2002-05-14 02:58, Simon Marlow wrote:
I must admit I can't think of any compelling reasons for the change, other than the fact that this is functionality that we don't have at the moment, and therefore might be useful. Opinions?
I need a function that does this: evaluate :: a -> IO a evaluate _|_ = fail something evaluate a = return a The idea is that you can take something that might be bottom and safely handle it in the IO monad, with the "bottomness" gone. This is what Exception.evaluate currently does, and I think that's correct. I think the behaviour of Exception.catch is wrong. I think it should behave like this: catch _|_ cc = _|_ catch (failure ex) cc = cc ex catch (success a) cc = success a ...whereas it actually behaves like this: catch _|_ cc = cc something catch (failure ex) cc = cc ex catch (success a) cc = success a -- Ashley Yakeley, Seattle WA