Re: RfD: more powerful "any" types

On Tue, 2009-09-08 at 10:23 -0700, David E. Wheeler wrote:
> On Sep 8, 2009, at 10:15 AM, Tom Lane wrote:
>
> >> arg_a IS DISTINCT FROM arg_b
> >
> > Surely you'd want arg_a and arg_b constrained to the same type,
> > otherwise there is no certainty that that means anything at all.
>
> Yes, for the purposes of pgTAP perhaps so. Then it's on the user to do
> the cast, because she decides that the cast is appropriate. Otherwise,
> as I said, perhaps it'd be too magical.

That's beginning to sound a bit like a generics feature. E.g.,

CREATE FUNCTION the_same<T>(arg_a T, arg_b T) RETURNS bool AS $$
SELECT arg_a IS DISTINCT FROM arg_b;
$$;