Re: Re: [PATCHES] Select parser at runtime

> Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> writes:
>
> > Ian Lance Taylor <ian(at)airs(dot)com> writes:
> > > For example: the datatypes have different names; the set of reserved
> > > words is different; Oracle uses a weird syntax for outer joins.
> >
> > Is it really possible to fix these things strictly in the parser
> > (ie, without any semantic analysis)? For example, I don't quite see
> > how you're going to translate Oracle-style outer joins to SQL standard
> > style without figuring out which fields belong to which relations.
> > Keep in mind the cardinal rule for the parsing step: Thou Shalt Not
> > Do Any Database Access (because the parser must work even in
> > transaction-aborted state, else how do we recognize ROLLBACK command?)
>
> I admit that I haven't sorted out the outer join thing yet. The
> others are easy enough.
>

Another idea is to put the Oracle stuff in gram.y, but use #ifdef or
something to mark the Oracle parts, and run gram.y through yacc/bison
with the Oracle defines visiable, and another time to create a second
parse state machine without Oracle. I think Jan did that for something
like that once.

--
Bruce Momjian | http://candle.pha.pa.us
pgman(at)candle(dot)pha(dot)pa(dot)us | (610) 853-3000
+ If your life is a hard drive, | 830 Blythe Avenue
+ Christ can be your backup. | Drexel Hill, Pennsylvania 19026