On Mon, Jan 19, 2009 at 3:58 AM, Patai Gergely <patai_gergely@fastmail.fm> wrote:

However, there are other type classes that are too general to assign
such concrete uses to. For instance, if a data structure can have more
than one meaningful (and useful) Functor or Monoid instance,

As a side curiosity, I would love to see an example of any data structure which has more than one Functor instance. Especially those which have more than one useful functor instance.

Luke