Finds a known inferencing state.
find-inferencing-state name &key if-does-not-exist => state
An inferencing state.
Finds and returns an inferencing state named by name.
If an inferencing state with the same name already exists (as compared using
eql), it is returned.
Otherwise, the value of if-does-not-exist determines what happens:
A continuable error is signaled. Invoking the
continue restart creates and returns a new inferencing state.
A new inferencing state is created and returned.
KnowledgeWorks and Prolog User Guide (Unix version) - 24 Mar 2017