Hello, I recently started to use DSL template within my rules. In the LHS, I oftenly match conditions against multiple facts, facts that I want to modify in the RHS. example : when $v1 : Variable(id == "A") $v2 : Variable(id == "B") then $v1.setFoo(); end If I write a dsl template like that : [when] there is "{id}"=v:Variable(id == "{id}") [then] foo me=v.setFoo(); and a dsl rule like that when there is "A" there is "B" then foo me end the execution will produce the error "Duplicate declaration for variable ..." I understand why it occurs. how to specify a constraint upon the fact matched ? Dunno if it is possible, my opinion will be to create another dsl rule, that is supposed to match with the "foo me", but it does not seem to be very convenient. Is there a way to use an array for variable assignement in the RHS ? like [when] there is "{id}"=v[]:Variable(id == "{id}") [then] foo me=v[].setFoo(); and use it in the RHS of the rule like when there is "A" there is "B" then foo me [0] // will cause foo me on the first matched fact end There are a lot of chances this does not exist, and works like that, maybe I am not using DSL well and it is bad idea to match multiple fact with the same dsl template. Can someone help me on that ? It is just a question, I am not stuck on this, but interested on how to deal with that. Thanks. Erik