Dan Piponi wrote:
No, definitely the new one. The old one is:newtype ListT m a = ListT { runListT :: m [a] } which treats the entire list as one uninterleavable lump. The new one is: data MList' m a = MNil | a `MCons` MList m a type MList m a = m (MList' m a) newtype ListT m a = ListT { runListT :: MList m a }
OK.
Note the definition of MList' is isomorphic to a use of Maybe.
Yes, and in fact http://www.haskell.org/hawiki/ListTDoneRight_2fAlternative1 uses exactly your type. But the old broken ListT happens to work fine here. See my earlier post in this thread. Regards, Yitz _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
