Re: [rules-users] Accepted idiom for binding variable to restriction?

Syntactically speaking, I don't think the eval is necessary: $response : Response( $question : question, question.ID == "XYZ" ) Behind the scenes Drools will still generate an eval to resolve the nested property constraint, but the rule stays simple to read and maintain. Edson 2010/6/2 Wolfgang Laun <wolfgang.laun(a)gmail.com&gt; The "inline eval" constraint is what you want: a boolean expression, > within parentheses. > > $response : Response( $question : question, > eval(question.getID().equals( "XYZ" ) ) ) > > See the Drools Expert manual, section on "Left Hand Side..." > > -W > > > On 1 June 2010 23:54, Laird Nelson <ljnelson(a)gmail.com&gt; wrote: > >> I have a fact that is inserted into my rule base. It is a Response. >> >> A Response has a Question that it is a response to. At the moment, >> the Question itself is not separately inserted into the knowledge >> base. I would ideally like to keep it this way. >> >> What's the best approach for binding variables to both the Response >> and its associated Question? >> >> That is, if the Question were inserted, it would be relatively easy: >> >> when >> $question : Question( ) >> $response : Response( question == $question ) >> >> ...but I'm finding myself somewhat confused how to "extract" a >> Question out of a Response, particularly when, say, I want to "select" >> only Responses whose associated Question IDs are "XYZ": >> >> when >> $response : Response( $question : question.ID == "XYZ" ) // boy >> howdy does this seem wrong >> >> Is the easiest thing to do here to add a second rule that just inserts >> the questions: >> >> when >> $response : Response >> then >> insert($response.getQuestion()) >> end >> >> ...? I would love to stay away from this if I could. >> >> Thanks, >> Laird >> _______________________________________________ >> rules-users mailing list >> rules-users(a)lists.jboss.org >> https://lists.jboss.org/mailman/listinfo/rules-users >> > > > _______________________________________________ > rules-users mailing list > rules-users(a)lists.jboss.org > https://lists.jboss.org/mailman/listinfo/rules-users > > -- Edson Tirelli JBoss Drools Core Development JBoss by Red Hat @ www.jboss.com _______________________________________________ rules-users mailing list rules-users(a)lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users