Re: [rules-users] comparing an intersection of sets..

It is possible to hide the eval for computing the intersection in a DSL. Given public class Element { private String name; private Set<Integer> numbers; public Element( String name, Integer... numbers ){ ... } // getters... public boolean disjointWith( Element other ){ Set<Integer> ownNumbers = new HashSet<Integer>( this.numbers ); ownNumbers.retainAll( other.getNumbers() ); return ownNumbers.isEmpty(); } } and the dsl [when]There is an element {eVar}={eVar} : Element() [when]- called {nVar}={nVar} : name [when]- other than {oVar}=this != {oVar} [when]- where {eVar} is disjoint from {oVar}=eval( {eVar}.disjointWith( {oVar} ) ) [when]- where {eVar} intersects with {oVar}=eval( ! {eVar}.disjointWith( {oVar} ) ) [then]show disjoint {n1Var} and {n2Var}=System.out.println( {n1Var} + " and " + {n2Var} + " are disjoint."); [then]show intersecting {n1Var} and {n2Var}=System.out.println( {n1Var} + " and " + {n2Var} + " intersect."); you can write the drsl package appl.domain expander elements.dsl rule "find disjoint pairs" when There is an element e1 - called n1 There is an element e2 - called n2 - other than e1 - where e1 is disjoint from e2 then show disjoint n1 and n2 end On 25 August 2010 16:55, mechlife <gaiamech(a)gmail.com&gt; wrote: