Gavin,
Thanks for reviewing the code, and I'm glad to help.
"addative" - D'oh! I copied those rules from a Java grammar. The copy-paste
anti-pattern strikes again. :)
I should be able to start working on an SQL producing examples in the next
few days. I will take a look at net.sf.hibernate.persister.Queryable, and
start a 'tree walker' grammar to round out a typical ANLR source translator
in the typical 'three phase' ANTLR fasion (lexer->parser->tree parser).
Here are some questions I had:
* Can this be done by just invoking the methods in the Hibernate JAR for
now, or do I need to build Hibernate? Either way, which version of the
Hibernate API should I use?
* How do I:
- Load and read Hibernate configurations?
- Read information about 'dialects'?
- Invoke SQL generating APIs?
* Should I add SQL-99 functions to the grammar?
Others have mentioned adding SQL-99 functions to the grammar and using them
to portably translate into the proper dialect. Since some of the SQL-99
functions have their own (IMHO, weird and unnecessary) syntax, they must be
added to the grammar. For example:
concatentate : "CONCATENATE" '(' expression ( '||' expression )* ')'
;
BTW,
I've seen much more 'inelegant' hand written parsers before (written in
FORTRAN and assembly), your's isn't too bad at all.
> -----Original Message-----
> From: Gavin King [mailto:[EMAIL PROTECTED]
> Sent: Thursday, November 20, 2003 3:16 AM
>
> OK, looks really great. So, now that we have a really nice
> grammar for HQL, whats the next step?
>
> Well, lets get it to spit out some SQL, I suppose. I think
> the first step is to get it to translate:
>
> from Foo foo where foo.id = 1
>
> to SQL, given a mock instance of net.sf.hibernate.persister.Queryable.
>
> Joshua, I know little about building proper compilers (I know
> a very little about parser compilers, but thats all) and it
> is universally agreed that my only previous attempt at it
> (net.sf.hibernate.hql) is ..... inelegant ..... so it would
> be fantastic if you could get me as far as showing me a
> proper design pattern for this. It would be fantastic if you
> could implement the above for me, to demonstrate what a
> proper translator looks like - that way I can pick up the
> other side of things (spitting out SQL) and integrate into Hibernate.
>
> I'd like to really keep moving with this - its really good
> and we need it....
>
> Thanks
>
> Gavin
>
> P.S. "addative" is spelled "additive" ;)
>
> Joshua Davis wrote:
>
> > I've checked my code into my own CVS repository on Source Forge, in
> > case anyone wants to have a look. Cleaned things up a bit,
> the tests
> > should run anyway. The build depends on: ANT, ANTLR, and JUnit
> >
> > [EMAIL PROTECTED]:/cvsroot/yajul Module=hql
> >
> > Web view: http://cvs.sourceforge.net/viewcvs.py/yajul/hql
> >
> > Check it out. (pun intended... sorry!)
> >
> >
> --
> Gavin King
> JBoss Group
> +61 410534454
> http://hibernate.org
>
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