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. ;)