[rules-dev] A dazzling feature - not in Drools!

[Raphael Duarte Paiva]

I totally agree with Wolfgang here.

On Thu, Aug 26, 2010 at 11:21, Wolfgang Laun <wolfgang.laun at gmail.com>wrote:

> I am surprised, all the more so because (cf. Expert):
>
>  "Each rule has a salience attribute that can be assigned an integer *
> number*,"
>
> This does not event remotely indicate that you can use an *expression*involving bound variables.
>
> If it isn't documented, nobody will use it. Being in front of the when part
> where the bindings occur, it is counter-intuitive to other bound variable
> references, and so I didn't even try.
>
> However: good to know, and thanks!
>
> -W
>
>
>
> On 26 August 2010 15:21, Edson Tirelli <tirelli at post.com> wrote:
> >     Wolfgang,
> >     Not sure I understand what you mean, but Drools supports dynamic
> > salience:
> > rule "fire in rank order 1,2,..."
> >       salience( -$rank )
> > when
> >       Element( $rank : rank,... )
> >       ...
> > then
> >      ...
> > end
> >     Edson
> >
> > 2010/8/26 Wolfgang Laun <wolfgang.laun at gmail.com>
> >>
> >> Just FYI, but who knows ;-)
> >>
> >> Our proprietary vintage RBS has a feature is (admittedly) rarely used
> >> but could come in handy, every now and then.
> >>
> >> Given this class
> >>
> >>   class Element {
> >>       int rank; // rank > 0
> >>   }
> >>
> >> and to fire a rule in ascending rank order, you can write (using
> >> modified Drools syntax)
> >>
> >> rule "fire in rank order 1,2,..."
> >> when
> >>       Element( $rank : rank,... )
> >>       // ...
> >> salience -$rank    ### <=
> >> then
> >>      // ...
> >> end
> >>
> >> The dynamically set salience does all the work. (Of course, you can
> >> achieve the same order
> >> in Drools easily enough.)
> >>
> >> This is possible since salience is a value that must be carried over
> >> into the activation.
> >> There is at least one other rule attribute that shares this property,
> >> but I'm not sure
> >> whether anything useful can be done with dynamic agenda groups.
> >>
> >> Cheers
> >> -W
> >> _______________________________________________
> >> rules-dev mailing list
> >> rules-dev at lists.jboss.org
> >> https://lists.jboss.org/mailman/listinfo/rules-dev
> >
> >
> >
> > --
> >   Edson Tirelli
> >   JBoss Drools Core Development
> >   JBoss by Red Hat @ www.jboss.com
> >
> > _______________________________________________
> > rules-dev mailing list
> > rules-dev at lists.jboss.org
> > https://lists.jboss.org/mailman/listinfo/rules-dev
> >
> >
>
>
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>
>


-- 
Abraços
Raphael Duarte Paiva
Graduando em Ciência da Computação

"For millions of years, mankind lived just like the animals. Then something
happened which unleashed the power of our imagination. We learned to talk
[...]" - Stephen Hawking, 1993
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