anchor.diff:    (with-tree-iterator (key left-token tree)
       (when (or (not (has-tests-p self))
                 (run-tests self left-token (get-top-fact right-token)))
  -      (pass-new-token self right-token left-token)))
  +      (pass-token-from-left self right-token left-token)))
     (values nil))
  
positive.code: (defmethod call-node-left ((self node2-not) (token add-token))
    (call-next-method self (make-clone-token (class-of token) token)))
  
  (defmethod run-tests-vary-right ((self node2-not) left-token tree)
    (with-tree-iterator (key right-token tree)
      (when (or (not (has-tests-p self))
                (run-tests self left-token (get-top-fact right-token)))
        (increment-negation-count left-token)))
    (unless (is-negated-p left-token)
      (with-accessors ((engine get-engine)) self
        (let ((token (make-derived-token
  
negative.code: ;;; File: node2-not.lisp
  ;;; Description: Specialized two-input node for negated patterns.
  
  ;;; $Id: node2-not.lisp,v 1.4 2000/12/12 00:09:32 youngde Exp $
  
  (in-package :lisa)
  
  