anchor.diff:  
   (defun reset-focus-stack (rete)
     (setf (rete-focus-stack rete)
  -    (list (find-context rete :initial-context) (rete-focus-stack rete))))
  +    (list (find-context rete :initial-context))))
   
   (defun set-initial-state (rete)
     (forget-all-facts rete)
  
positive.code: ;;; File: rete.lisp
  ;;; Description: Class representing the inference engine itself.
  
  ;;; $Id: rete.lisp,v 1.38 2002/11/19 19:41:14 youngde Exp $
  
  (in-package "LISA")
  
  
negative.code: (defmethod add-activation ((self rete) activation)
    (trace-enable-activation activation)
    (add-activation
     (context-strategy (rule-context (activation-rule activation))) activation))
  
  (defmethod disable-activation ((self rete) activation)
    (when (eligible-p activation)
  