I find myself dismayed that the mathematical relationship between Monads and Functors isn't available in Haskell98; if I use fmap in a Monad m=>... typed function, I get an extra Functor m required in the context, but not only are all mathematical monads functors, any instance of Monad has fmap in the form (>>= return . f), so it's annoying. There has been discussion in the past about whether Monad should be defined as
class Functor m => Monad m where ...
(or some other means of making all Monads instances of Functor) I think the general consensus on the libraries mailing list in this thread http://thread.gmane.org/gmane.comp.lang.haskell.libraries/2815/focus=2815 which refers to this: http://www.cs.chalmers.se/~rjmh/Haskell/Messages/Display.cgi?id=444 was that it would be a good thing, but it breaks Haskell98 programmes. Surely Haskell' can get this right? On haskell prime I can find http://thread.gmane.org/gmane.comp.lang.haskell.prime/1328/focus=1427 which agrees with me, but I don't see a definite decision either there or in the Trac. I'd favour the above method as most conservative in terms of the language, but I'm not too fussed how it happens. Jón -- Jón Fairbairn Jon.Fairbairn at cl.cam.ac.uk