Re: [Haskell-cafe] Adding Ord constraint to instance Monad Set?

This syntax would also have the advantage that you can apply different contexts to different constructors.

Er, you can already do that as I just pointed out: data (Ord a,Num b) => Either a b = Left a | Right b Note that to constrain the same type variable differently for different constructors would be a type error. In other words this: data Either a = Num a => Left a Ord a => Right a Is not valid, because (forall a . Num a) is not the same type as (forall a . Ord a). So infact the current way of writing it as data (Num a) => Either a = Left a | Right a Is better because it does not allow you to make that mistake. Regards, Keean.