First run the tutorial example a few times. Think of an animal and type
(infer) into the listener.
infer is a function which starts the forward chaining engine. Popup question windows will appear, which require clicking on either
. If your animal is guessed correctly, execution will terminate and the listener prompt will reappear. If the final guess is incorrect then:
Return(or click on OK ). If the animal is already known to the system this constitutes an error. A confirmer popup will inform you of this; click on Confirm and execution will terminate.
Return. Execution will terminate.
(infer)again in the listener. This time the system will know about your new animal and the question that distinguishes it. Every time the rule interpreter finishes, it will return and display in the listener the number of rules the forward chaining engine fired.
KnowledgeWorks and Prolog User Guide (Macintosh version) - 24 Mar 2017