anchor.diff:  ;;; File: network-ops.lisp
   ;;; Description:
   
  -;;; $Id: network-ops.lisp,v 1.14 2002/10/08 18:34:31 youngde Exp $
  +;;; $Id: network-ops.lisp,v 1.15 2002/10/08 18:54:45 youngde Exp $
   
   (in-package "LISA")
   
  
positive.code:            (merge-root-node (new-root)
               (let ((existing-root
                      (find-root-node to-rete new-root)))
                 (if (null existing-root)
                     (add-new-root to-rete new-root)
                   (merge-successors
                    existing-root (shared-node-all-successors new-root))))))
      (let ((*node-set* (list)))
        (loop for new-root being the hash-value
            of (rete-roots from-rete)
  
negative.code:     (increment-use-count parent))
    (push (make-node-pair node parent) *node-set*))
  
  (defmethod add-node-set ((parent join-node) node &optional count-p)
    (declare (ignore node count-p))
    nil)
  
  (defmethod add-node-set (parent node &optional count-p)
    (declare (ignore count-p))
    (push (make-node-pair node parent) *node-set*))
  
  (defun merge-networks (from-rete to-rete)
    (labels ((find-root-node (network node)
  