On Mon, Nov 29, 2010 at 11:26 AM, Isaac Dupree
On 11/29/10 03:39, John Smith wrote:
Is there any intention to reorganise the standard class hierarchy, arranging them logically instead of in order of invention? I plagiarised the following example from http://stackoverflow.com/questions/1634911/can-liftm-differ-from-lifta and Trac:
class Functor f where map :: (a -> b) -> f a -> f b
class Functor f => Pointed f where pure :: a -> f a
Is it useful to have Pointed non-Functors?
Is Pointed useful at all? The last time this discussion came up, I
asked for algorithms which were generic over pointed functors (in the
same way that traverse is generic over applicative functors) and no
one could think of any.
Without <*> or >>=, all we can say about pure is that it's a natural
transformation.
--
Dave Menendez