O'Haskell OOP Polymorphic Functions

Lennart Augustsson lennart@mail.augustsson.net
Wed, 17 Jan 2001 20:03:14 -0500

Ashley Yakeley wrote:

> This seems to be stretching the concept of 'subtype'.

I don't think so, this is the essence of subtyping.

> Sorry if I sound so bitter and disappointed. I was hoping for a Haskell
> extended with real dynamic subtyping...

You seem to want dynamic type tests.  This is another feature, and
sometimes a useful one.  But it requires carrying around types at
You might want to look at existential types; it is a similar feature.

    -- Lennart