Re: [rules-dev] Perhaps an undocumented feature of Backward Chaining?

** On 23/06/2011 13:20, Wolfgang Laun wrote: Still not resolved... I have added a test for all the possible insertion orders for that particular use case and was not able to reproduce a problem: https://github.com/droolsjbpm/drools/commit/501f2196dcef754eed5a28b066b50... MArk On 22 June 2011 21:40, Mark Proctor <mproctor(a)codehaus.org&gt; wrote: > heh, I made a mistake with the rule > ( Location(z, y;) and ?hasFood(x, z;) ) > should be > ( Location(z, y;) and hasFood(x, z;) ) > > Otherwise it's not reactive, and then ordering matters. > > With that change I can do the insertions in any order and all is fine. > > This works for the example you gave. But the one taken from the "Introduction" still depends on the order the facts are inserted. Below is the .drl, which does not need any pojos. Rule kickOff contains the order that produces nothing to see and eat: You are in the table You can see [] You can eat [] Insert Here after the others, and it works. -W import java.util.List declare Thing thing : String @key end declare Edible extends Thing end declare Location extends Thing location : String @key end declare Here place : String end rule kickOff when then System.out.println( "insert Here" ); insert( new Here( "table" ) ); System.out.println( "insert Edible" ); insert( new Edible( "peach" ) ); System.out.println( "insert Location" ); insert( new Location( "peach", "table" ) ); end # 2011-06-22 query isContainedIn( String x, String y ) Location(x, y;) or ( Location(z, y;) and /*?*/isContainedIn(x, z;) ) end query whereFood( String x, String y ) ( Location(x, y;) and Edible(x;) ) or ( Location(z, y;) and /*?*/whereFood(x, z;) ) end query look(String place, List things, List food) Here(place;) things := List() from accumulate( Location(thing, place;), collectList( thing ) ) food := List() from accumulate( /*?*/whereFood(thing, place;), collectList( thing ) ) end rule reactiveLook when Here( $place : place) /*?*/look($place, $things; $food := food) then System.out.println( "You are in the " + $place); System.out.println( " You can see " + $things ); System.out.println( " You can eat " + $food ); end _______________________________________________ rules-dev mailing list rules-dev@lists.jboss.orghttps://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