With the instances Ryan suggests, the type seems to belong to
Control.Applicative rather than Data.Monoid.
On Wed, Apr 11, 2018, 1:25 PM Ryan Scott
One thing that is not clear to me: is this Ap type intended to be a catch-all for defining instances that are "lifted" through an Applicative? Or are you deliberately restricting that to the Semigroup and Monoid instances? For instance, I noticed that you currently derive Ap's Eq, Ord, Read, and Show instances, which would give:
instance Eq (f a) => Eq (Ap f a) instance Ord (f a) => Ord (Ap f a) instance Read (f a) => Read (Ap f a) instance Show (f a) => Show (Ap f a)
Would you not want this instead, to be in line with the Semigroup and Monoid instances?
instance (Applicative f, Eq a) => Eq (Ap f a) instance (Applicative f, Ord a) => Ord (Ap f a) instance (Applicative f, Read a) => Read (Ap f a) instance (Applicative f, Show a) => Show (Ap f a)
I would be fine with either option, but if we should be clear about Ap's intentions when we end up documenting it.
Ryan S. _______________________________________________ Libraries mailing list Libraries@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/libraries