Re: RfD: more powerful "any" types

Peter Eisentraut wrote:
> 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 $$
> SELECT arg_a IS DISTINCT FROM arg_b;
> $$;

Well, you can write that one with anyelement already.

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Alvaro Herrera http://www.CommandPrompt.com/
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