[rules-users] Using "in" or "not in" operator in a DSL

Hi folks, I'm trying to create a DSL where the user should be able to add a bunch of values, as when using the normal rule syntax. The DSL should look something this: when person is not "18","21", "100" years old then normal birthday end My problem is I don't know the number of arguments. When I write a normal rule I can say somethink like: Age (value in ("18","21","100")) But how can I achieve this in a DSL syntax? Thanks Joerg