Re: proposal for 8.3: Simultaneous assignment for PL/pgSQL - Mailing list pgsql-hackers

From Tom Lane
Subject Re: proposal for 8.3: Simultaneous assignment for PL/pgSQL
Date
Msg-id 2921.1154970700@sss.pgh.pa.us
Whole thread Raw
In response to Re: proposal for 8.3: Simultaneous assignment for PL/pgSQL  (Martijn van Oosterhout <kleptog@svana.org>)
Responses Re: proposal for 8.3: Simultaneous assignment for PL/pgSQL
List pgsql-hackers
Martijn van Oosterhout <kleptog@svana.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


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