doing %-expansion in plpgsql RAISE USING

Alvaro Herrera <alvherre@commandprompt.com> writes:

It seems there's no way to do %-expansion in plpgsql when one is using
RAISE USING:

That's intentional. Just use string concatenation if you need a
run-time-variable message.

regards, tom lane

Hello

2009/8/4 Alvaro Herrera <alvherre@commandprompt.com>:

Hi,

It seems there's no way to do %-expansion in plpgsql when one is using
RAISE USING:

alvherre=# create or replace function f () returns void language plpgsql as $$
begin
 raise using message = 'hello %' || 'world';
 return;
end;
$$;
CREATE FUNCTION
alvherre=# select f();
ERROR:  hello %world

parameter is expression, so we could to define operator % like

text % any

% isn't defined for text so this is possible. This operator should be
generally used, not only in RAISE attribs.

I would like the % to be expanded to some argument, but obviously
there's no way to pass the arguments that it should expand to.  We could
do something like

RAISE USING message = 'hello %st %', args = 1, 'world'

RAISE USING message = 'hello %st %' % (1, 'world')

??

or simple use custom variadic function

RAISE USING message= subst('hello %st %', 1, 'world')

good example for parser hook :)

Pavel

Tom Lane wrote:

Alvaro Herrera <alvherre@commandprompt.com> writes:

It seems there's no way to do %-expansion in plpgsql when one is using
RAISE USING:

That's intentional. Just use string concatenation if you need a
run-time-variable message.

Yes, I can do that, but it's really ugly and gets unmaintainable
quickly.

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