
 Figure 5.2 KnowledgeWorks Listener
 The KnowledgeWorks Listener is obtained by choosing KnowledgeWorks > Listener from the KnowledgeWorks Podium. This tool is based on the LispWorks Common Prolog Logic Listener (see Appendix A, Common Prolog for further details). Input is taken as being a goal expression to be satisfied unless no predicate of that name and arity (number of arguments) exists in which case it is taken as a Lisp expression. That is, the input may be either
 <expression>as defined in Forward chaining, or
 <lisp-expr> with the former interpretation taking priority when ambiguous. Interaction is Prolog-style, so when the bindings which satisfy a goal are printed, pressing RETURN terminates execution, and entering ; (semi-colon) and RETURN (or just clicking on the  Next button at the bottom) looks for the next solution to the goal.
The File , Leashing and Spy menu options behave as for the Common Prolog Logic Listener (see Appendix A, Common Prolog) and the Value , Restart and History options behave as for the Lisp Listener (see the Common LispWorks User Guide ).