Pavel Stehule <pavel.steh...@gmail.com> writes: > some years ago there was some plans about parser's extensibility. I am > able write bison extensions, but I thing, so lot of work should be > done via hooking of transform stage.
This strikes me as next door to useless, because it can only handle things that look like valid expressions to the existing grammar. So pretty much all you can do is weird sorts of functions, which are already accommodated at less effort with existing features such as function overloading. A hook check in that particular place is not going to have negligible performance impact, since it's going to be hit tens or hundreds or thousands of times per query rather than just once. So it's going to require more than a marginal use case to persuade me we ought to have it. regards, tom lane -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers