[Haskell-cafe] (Co/Contra)Functor and Comonad

Mario Blažević mblazevic at stilo.com
Fri Dec 24 05:46:39 CET 2010


On Thu, Dec 23, 2010 at 11:25 PM, Tony Morris <tonymorris at gmail.com> wrote:

>
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> ...regardless of the utility of a contravariant functor type-class, I
> strongly advocate for calling it Contrafunctor and not Cofunctor. I
> have seen numerous examples of confusion over this, particularly in
> other languages.
>


I don't personally care what's it called, as long as it's available. Can
anybody point to an authoritative source for the terminology, though?
Wikipedia claims that cofunctor is a contravariant functor.

Also, is there anything in category theory equivalent to the Functor ->
Applicative -> Monad hierarchy , but with a Cofunctor/Contrafunctor at the
base? I'm just curious, I'm not advocating adding the entire hierarchy to
the base library. ;)
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