rank 2-polymorphism and type checking

Carl R. Witty cwitty@newtonlabs.com
24 Oct 2001 12:43:20 -0700

"Simon Peyton-Jones" <simonpj@microsoft.com> writes:

> So I'm interested to know: if GHC allowed arbitrarily-ranked types, who
> would use them?

I can't promise that I would use them, but it would certainly give me
warm fuzzy feelings to know that they were there. :-)

On the other hand, I believe that you can construct in GHC a type
which is isomorphic to any arbitrarily-ranked type (with any
combination of existential and universal quantification) by creating
new data constructors.  If this is true, then I'm reasonably content
with that.

Carl Witty