On Mon, Sep 16, 2013 at 4:57 AM, Michael Snoyman <michael@snoyman.com> wrote:

I think I just made a bad assumption about what you were proposing. If I was going to introduce a typeclass like this, I'd want it to support `Set`, since IME it's the most commonly used polymorphic `map` operation that has constraints. (Note that HashMap and Map are in fact Functors, since mapping only affects their values, which are unconstrained.) I don't really have any strong feelings on this topic, just that it would be nice to have some kind of a map-like function that worked on Set and HashSet.

Ok, understood.  I most often use this with Data.Vector.Unboxed and Data.Vector.Storable, and that it would be useful for Set didn't really occur to me.

Given that, I agree that a non-Functor name is a workable choice.