Re: "fix" for plpgsql polymorphism

I'm going to resend the patches that I have outstanding since it appears
some may have been lost. Here's the first.
==========================================

Tom Lane wrote:
>>You can alias $0, similar to the argument variables. And, I confirmed
>>that you cannot change the value, similar to the argument variables:
>
> Perhaps you shouldn't mark it isconst; then it would actually have some
> usefulness (you could use it directly as a temporary variable to hold
> the intended result). I can't see much value in aliasing it if it's
> const, either.

OK; the only change in this version is "isconst = false;". Now you can
use $0 as a result placeholder if desired. E.g.:

create or replace function tmp(anyelement, anyelement) returns anyarray as '
declare
v_ret alias for $0;
v_el1 alias for $1;
v_el2 alias for $2;
begin
v_ret := ARRAY[v_el1, v_el2];
return v_ret;
end;
' language 'plpgsql';

create table f(f1 text, f2 text, f3 int, f4 int);
insert into f values ('a','b',1,2);
insert into f values ('z','x',3,4);

select tmp(f1,f2) from f;
select tmp(f3,f4) from f;

Joe