On Mon, Nov 29, 2010 at 11:26 AM, Isaac Dupree <ml@isaac.cedarswampstudios.org> wrote:
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 <dave@zednenem.com> <http://www.eyrie.org/~zednenem/>