Re: [rules-dev] Drools syntax diagrams - redrawn

On 22/09/2010 14:40, Wolfgang Laun wrote: > Service: > http://www-cgi.uni-regensburg.de/~brf09510/syntax.html > <http://www-cgi.uni-regensburg.de/%7Ebrf09510/syntax.html> > > The grammar syntax is the same as used in DRL.g but stripped of all > the antsy additions, and simplified. > > @Mark: I'm well aware of the limitations of a 1:1 translation of a > parser's grammar into diagrams. I have reduced the splits into > separate rules in DRL.g considerably. But what do you want to hide > from the users? The syntax is the syntax, and there's no > sweet-talking around it after you have reduced all the noise from > technical splits. > > One thing that might help would be deprecating things like infix or/and. yes agreed. Simplifying the grammar, reducing ambigiiouty or multiple ways of doing the same thing, will make any resulting grammar both easier ot maintain and grok. Edson, Davide and I have already discuss this. Both are working on a new parser and are trying to address these issues. So things that are doing are: Single binding on 'or' $binding : ( Pattern() || Pattern() ) We are thinking of only allowing 'or' between patterns and not allowing users to mix and match 'or' and '||'. Inside of patterns '||' is the only connective allowed and will remain so. We will also probably make a choice and only allow infix 'or' and 'and', at the moment users can chose infix or prefix. Personally I find prefix quite attractive as it works sort of like a "choice": (or Person( ... ) Person( ... ) Person( ...) ) But I think most peopel are more comfortable with infix: (Person( ... ) or Person( ... ) or Person( ...) ) return value, eval, literal constraint, variable constraint are going. These are left overs of a Clips based grammar. So instead we'll have a generic "expr" class that follow more common modern ASTs for expression engines, like say MVEL. Davide has also requested that we make $ prefix mandatory for LHS bindings as that is deterministic and again makes the grammar cleaner. I personally like it being optional and it's still open to debate. But I recognise the need to have better maintained grammar, that is more consistent and regular with easy to main documentation. Mark

> > Some rules can be omitted if they coincide with Java's own rules; > just add an explanation. > > -W > > > On 22 September 2010 14:56, Anstis, Michael (M.) <manstis1(a)ford.com > <mailto:manstis1@ford.com>> wrote: > > What was the service and was it the ANTLR grammar you uploaded to > generate the images? > > Thanks, > > Mike > > -----Original Message----- > From: rules-dev-bounces(a)lists.jboss.org > <mailto:rules-dev-bounces@lists.jboss.org> > [mailto:rules-dev-bounces@lists.jboss.org > <mailto:rules-dev-bounces@lists.jboss.org>] On Behalf Of Wolfgang > Laun > Sent: 22 September 2010 13:38 > To: Rules Dev List > Subject: [rules-dev] Drools syntax diagrams - redrawn > > I've found this online service and stuffed the Drools grammar > into it. > > You may see the results while they are still there: > http://www-cgi.uni-regensburg.de/~brf09510/syntax.tmp/x45371x0x0x.ebnf.h > tml > <http://www-cgi.uni-regensburg.de/%7Ebrf09510/syntax.tmp/x45371x0x0x.ebnf.... > <http://www-cgi.uni-regensburg.de/%7Ebrf09510/syntax.tmp/x45371x0x0x.ebn > f.html > <http://www-cgi.uni-regensburg.de/%7Ebrf09510/syntax.tmp/x45371x0x0x.ebn%0... > > -W > > > > _______________________________________________ > rules-dev mailing list > rules-dev(a)lists.jboss.org <mailto:rules-dev@lists.jboss.org> > https://lists.jboss.org/mailman/listinfo/rules-dev > > > > _______________________________________________ > rules-dev mailing list > rules-dev(a)lists.jboss.org > https://lists.jboss.org/mailman/listinfo/rules-dev