This is about as good as you can do. The monad-loops package provides a
variety of similar combinators, generally implemented in similar ways, but
not this specific combinator. The downside of this combinator is that it is
partial: it will run forever without producing anything if f never gives a
Nothing.
On Thu, Jul 20, 2017 at 10:27 AM Jake
I have a function f :: a -> Maybe a that I want to feed into itself with some initial input until it returns Nothing.
untilNothing :: (a -> Maybe a) -> a -> a untilNothing f x = case f x of Just x' -> untilNothing f x' Nothing -> x
Is there a better way to do this? I feel like there is something more general going on with Monads being fed into themselves, but maybe I'm wrong. Thoughts? _______________________________________________ Haskell-Cafe mailing list To (un)subscribe, modify options or view archives go to: http://mail.haskell.org/cgi-bin/mailman/listinfo/haskell-cafe Only members subscribed via the mailman list are allowed to post.