Ashley Yakeley <ashley(a)semantic.org> writes:
> I currently have my own implementations for these:
> instance Foldable Identity
> instance Traversable Identity
> instance Applicative Identity
The transformers package has such instances (but currently for a different
Identity type).
> instance Foldable (Either p)
> instance Traversable (Either p)
> instance Applicative (Either p)
> instance Foldable ((,) p)
> instance Traversable ((,) p)
The Applicative one is proposed here. The others should also be added.