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? (I.e. not superclass). Er, Data.Set is the only example I've come up with (its 'singleton' doesn't require Ord on elements but its 'map' does). Then you'd have things like class (Pointed f, Functor f) => Applicative f where Cons: Pointed doesn't have any laws without Functor Pros: (pure) might be useful to use generically by itself -Isaac