Bulat Ziganshin wrote: > instead of writing > foo :: (Num a, Monad m) => a -> m () > allow to write > foo :: Num -> Monad ()
as has been noted, that would be special treatment for unary type classes with argument of kind *. Also, *if* we want such a shorthand, it is not clear whether we want existential or forall typing per default. Referring to your example, the "foo" function must be able to return a value in *each* monad that the caller specifies at the call site, while we were discussing functions that make their own choice of returning *some* monad instance. Best regards, -- -- Johannes Waldmann -- Tel/Fax (0341) 3076 6479/80 -- ---- http://www.imn.htwk-leipzig.de/~waldmann/ ------- _______________________________________________ Haskell-prime mailing list Haskell-prime@haskell.org http://haskell.org/mailman/listinfo/haskell-prime
