foralls in class assertions

Ashley Yakeley
Fri, 1 Mar 2002 22:23:26 -0800

At 2002-02-20 13:15, Simon Peyton-Jones wrote:

>I have not implemented, yet.  As always my implementation
>priorities are strongly influenced by my perception of whether
>some enhancement would be used.  Maybe you can outline
>why such a change would be useful to you?  I only have the
>example in our paper as motivation so far.

I just came across one. I want to create a class for refs, such that they 
are in Eq:

class (forall a. Eq (r a)) => Ref m r where
    newRef :: a -> m (r a);
    ... etc.

Ashley Yakeley, Seattle WA