From: Stephen Tetley <stephen.tetley@gmail.com>

On 6 September 2010 20:18, John Lato <jwlato@gmail.com> wrote:

> Can you give an example of a Functor that doesn't have pure? I think it's
> Pointed Functors which are useful; not Functor by itself.

Strictly speaking is Pair one? The current implementation tacks on monoid.

Interesting example. I tend not to like implementations which rely on bottoms, so I think I'd agree.

In a similar spirit, I would propose Data.Vector.Unboxed.Vector as a Pointed Functor (modulo element restrictions) which is not Applicative, since the necessary element restrictions mean <*> can't be defined.

John