Martijn van Oosterhout <kleptog(at)svana(dot)org> writes:
> Well, you can implement it. After all, the CALL syntax is merely
> syntactic sugar. You could (if you wanted to) do the following:
> CREATE FUNCTION foo( a TEXT IN, b TEXT INOUT, c TEXT OUT ) as blah...
> And in a pl/pgsql function, translate: "CALL foo(a,b,c)"
> into "(b,c) = foo(a,b)" internally.
No, Pavel's right: that doesn't work because it's ambiguous. How do you
tell whether "CALL foo(a,b,c)" means
a,b,c := foo();
b,c := foo(a);
c := foo(a,b);
select foo(a,b,c);
There could be functions foo matching all four interpretations.
regards, tom lane