RE: MonadZero (concluded?)

[Koen Claessen]

Simon Peyton-Jones wrote about Phil Wadler's idea:

 | Good idea!  So your suggestion is:
 | 
 |      class Monad m where
 |         ...return, >>=, >> as before...
 | 
 |         mfail :: String -> m a
 | 
 |      class MonadPlus m where
 |         mplus :: m a -> m a -> m a
 |         mzero :: m a

I hope you mean:

  class Monad m => MonadPlus m where
    mplus :: m a -> m a -> m a
    mzero :: m a

    mzero = mfail "mzero" -- maybe?

Regards,
Koen.

--
Koen Claessen,
[EMAIL PROTECTED],
http://www.cs.chalmers.se/~koen,
Chalmers University of Technology.