On Sun 17/01/10 4:47 PM , Twan van Laarhoven twanvl@gmail.com sent:

The Arrow class is too big, it includes too many things and it should be split up. This is yet another example. You can get some of the benefits of standard classes by making Transducer an instance of Control.Category.Category, for which you only need to implement (.) and id.

Yes, perhaps I'll do that. Is there any relatively accepted package that defines PointedCategory?