The backward chaining inference engine is started to look for any set of bindings which satisfy goal-to-prove. Using those bindings, pattern-to-instantiate is instantiated and returned.
Two values are returned. The second value indicates with t
that a proof was found, or with nil
that no proof exists. In the former case, the first value is the instantiated version of pattern-to-instantiate, in the latter case, the first value is nil
.
Any subgoals that match the object base will only find objects from the current inferencing state.
KnowledgeWorks and Prolog User Guide (Unix version) - 24 Mar 2017