[rules-users] Custom EvaluatorFactory

[Andy Mei]

Hi Mark,

>> what you are using there is a return value constraint, to the engine its
effectively a black box, and is evaluated by the chosen dialect; mvel or
java. So if you want ot be able to do that type of arithmetic, work with the
MVEL author to make sure its incuded in his engine.

I think Mvel do support return value constraint, no?

   http://docs.codehaus.org/display/MVEL/Basic+Syntax


On Dec 20, 2007 11:04 AM, Mark Proctor <mproctor at codehaus.org> wrote:

>  Andy Mei wrote:
>
> Hi Edson,
>
> This is exactly what I am looking for, thanks!
>
> One comment, is it possible to expand on list of operators Drools
> support?  Better yet, make it plugable just like EvaluatorDefinition.
>
> Not yet, this is something we want, but our current approach to using
> antlr has limited our flexability there. We would need to rewrite the
> grammar, using an antlr-tree parser, then we should be able to have user
> definable list of operators.
>
>
> Correct me if I am wrong, but here are list of operators Drools support:
>   http://anonsvn.labs.jboss.com/labs/jbossrules/trunk/drools-core/src/main/java/org/drools/base/evaluators/Operator.java
>
>
> Would it be possible if I could add additional operators like '+', '-',
> '/', '%'... to any objects.  For example, I would love to allow users to
> write syntax below, where user could subtract 3 days from the current day.
>
>   $p : Position ( settlementDate < ( $TODAY - '3D' ) )
>
> what you are using there is a return value constraint, to the engine its
> effectively a black box, and is evaluated by the chosen dialect; mvel or
> java. So if you want ot be able to do that type of arithmetic, work with the
> MVEL author to make sure its incuded in his engine.
>
>
> I love the project, keep up the good work.  I am negotiating with
> management to purchase support contract from Redhat.
>
> great :)
>
>
> Andy
>
> On Dec 19, 2007 6:26 PM, Edson Tirelli <tirelli at post.com> wrote:
>
> >
> >    Andy,
> >
> >    I just added support for that in trunk (drools-4.1.0.SNAPSHOT).
> > Although trunk is a work in progress, you are welcome to try it out and
> > check if it meets your needs and provide feedback. Look for the interface:
> > org.drools.base.evaluators.EvaluatorDefinition and its subclasses as
> > examples.
> >
> >    []s
> >    Edson
> >
> > 2007/12/19, Andy Mei < andy.d.mei at gmail.com >:
> > >
> > >  Hi,
> > >
> > >   Is there a way I could register my own custom EvaluatorFactory?
> > >   Drools ships with DateFactory what compares only dates, but no time
> > > is included.  I would like to compare time as well.
> > >   I see that it would be very helpful to include capability to
> > > register custom EvaluatorFactory.
> > >   Thanks.
> > >
> > > Andy
> > >
> > >  _______________________________________________
> > > rules-users mailing list
> > > rules-users at lists.jboss.org
> > > https://lists.jboss.org/mailman/listinfo/rules-users
> > >
> > >
> >
> >
> > --
> >   Edson Tirelli
> >   JBoss Drools Core Development
> >   Office: +55 11 3529-6000
> >   Mobile: +55 11 9287-5646
> >   JBoss, a division of Red Hat @ www.jboss.com
> > _______________________________________________
> > rules-users mailing list
> > rules-users at lists.jboss.org
> > https://lists.jboss.org/mailman/listinfo/rules-users
> >
> >
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