Hello Günther, I use ContT monads for early exit often, because that's one of the things they encode naturally. But I don't do this with callCC. I prefer monadLib over mtl/transformers, which has a specific function for that: abort :: (AbortM m i) => i -> m a where AbortM is a class for monads, whose computations are abortable. All ContT monads are instances. This is also a nice way to break out of 'forever'. Using an error monad (like Maybe) may be more natural of course. Greets, Ertugrul Günther Schmidt <gue.schmidt@web.de> wrote:
Hi everyone,
I'm about to write a rather lengthy piece of IO code. Depending on the results of some of the IO actions I'd like the computation to stop right there and then.
Now I know in general how to write this but I'm wondering if this is one of those occasions where I should make use of the Cont monad to make an early exit.
Günther
-- nightmare = unsafePerformIO (getWrongWife >>= sex) http://blog.ertes.de/