hello, Andrew J Bromage wrote:
G'day all.
On Sun, Jul 27, 2003 at 09:28:57PM +0200, Iavor Diatchki wrote:
in my other library i had a similar operation, corresponding to the fact that most monad transformers are functors on the category of monads. it works for all transformers except for continuations:
class MondaTrans t => MapTrans t where mapTrans :: (Monad m, Monad n) => (forall a. m a -> n a) -> t m b -> t n b
intuitively the "forall" constraint says that we are changing just the monad, and not touching the value. to get continuations to work, one needs a map (n a -> m a) as well, i think. any comments about that class?
Looks pretty good to me, though I still don't like the name. we could change it but to what?
bye iavor -- ================================================== | Iavor S. Diatchki, Ph.D. student | | Department of Computer Science and Engineering | | School of OGI at OHSU | | http://www.cse.ogi.edu/~diatchki | ==================================================