On 27-Aug-1999, Michael Hobbs <[EMAIL PROTECTED]> wrote:
> Those who are into the more esoteric aspects of OO know that an object
> has both a "type" (interface) and a "class" (implementation).
Yes, but of course Haskell uses those two words in the opposite sense!
In Haskell, a class specifies the interface while a type specifies the
implementation. This is an unfortunate clash of terminologies.
> The OO support that currently exists in Haskell only addresses an
> object's interface, and not very conveniently either. The reason I write
> "not very conveniently" is because there is kludgy support for interface
> inheritance
Could you elaborate here? What is kludgy about Haskell's support for
interface inheritence?
> and it is not possible to create a list of values that may
> be of different [Haskell] type, but all implement the same interface.
Existential types solve that problem.
Cheers,
Fergus.
--
Fergus Henderson <[EMAIL PROTECTED]> | "I have always known that the pursuit
WWW: <http://www.cs.mu.oz.au/~fjh> | of excellence is a lethal habit"
PGP: finger [EMAIL PROTECTED] | -- the last words of T. S. Garp.
