If anyone wants to help I started a Clips parser over the weekend. So far it can pass multi patters with bound variables, variable constraint, literal constraint, return value, predicate, as well as field connectives | and &. What is needed now is to get it working with 'not', 'exists', 'and', and 'or'. So far the following unit test works: RuleDescr rule = parse("(defrule xxx ?b <- (name (name \"yyy\"&?bf|~\"zzz\"|~=(ppp)&:(ooo)) )").rule(); I haven't got it parsing functions yet, figured I'd do that later once its abale to successfully parse the LHS, so it instead it picks up IDS "ppp" for the return value and "ooo" for the predicate. Mark