I assume you want to impose the MonadFix sliding law,
ffix (fmap h . f) = fmap h (ffix (f . h)), for strict h.
Do you also want the nesting law?
ffix (\x -> ffix (\y -> f x y)) = ffix (\x -> f x x)
Are there any other laws you'd like to add in place of the seemingly
irrelevant purity
and left shrinking laws?
Can you give some sample instances and how one might use them?
On Wed, Aug 30, 2017 at 2:59 PM, Wolfgang Jeltsch
Hi!
There is the MonadFix class with the mfix method. However, there are situations where you need a fixed point operator of type a -> f a for some f, but f is not necessarily a monad. What about adding a FunctorFix class that is identical to MonadFix, except that it has a Functor, not a Monad, superclass constraint?
All the best, Wolfgang _______________________________________________ Libraries mailing list Libraries@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/libraries