On Wed, 8 Jul 2009, Edward Kmett wrote:
+1 in favor of generalizing Endo in Data.Monoid.
In my monoids library I have a Data.Monoid.Categorical that includes a 'GEndo' generalized endomorphism over an arbitrary category and I would love to be able to remove it.
-Edward Kmett
I was looking for this in your lib, but I didn't find it. Anyhow, I'm also in favour of generalizing Endo. I was being conservitive with my initial proposal. Would we still have to pick a new name and then type Endo a = NewEndoName (->) a ?
In Data.Monoid there is
newtype Endo a = Endo { appEndo :: a -> a }
instance Monoid (Endo a) where mempty = Endo id Endo f `mappend` Endo g = Endo (f . g)
and (->) is an instance of Category, so perhaps we should generalize Endo.
The name EndoCategory seems wrong, as this won't be an instance of Category. Endomorphism? _______________________________________________ Libraries mailing list Libraries@haskell.org http://www.haskell.org/mailman/listinfo/libraries
-- Russell O'Connor http://r6.ca/ ``All talk about `theft,''' the general counsel of the American Graphophone Company wrote, ``is the merest claptrap, for there exists no property in ideas musical, literary or artistic, except as defined by statute.''