Re: ERROR action extension for rules?

>      CREATE RULE PasTouche AS ON UPDATE TO foo
>      WHERE old.locked=TRUE
>      DO INSTEAD ERROR;
> 
> I think this simple new rule action could be added to pg.
> I'm planning to do it, if there is no opposition.
> Any comments on this proposed new rule action?
> Or did I missed something obvious with rules?

I've often debated creating an sql elog function for the ELSE segment of
a CASE statement.