Functor => Pointed => Applicative => Monad

[Roman Leshchinskiy]

On 01/12/2010, at 13:04, Conor McBride wrote:

> I was being slightly facetious. I was also wondering what
> value the Pointed class would add, by asking which instances
> of Functor would fail to be Pointed. The constantly Zero
> (or Void, if you insist) Functor? What else?

Any tuple type. Or, more generally, any multifunctor or anything that carries more information than just the a.

Roman