anchor.diff:      (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 parent node count-p))
  -  nil)
  +  (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)
  
positive.code: ;;; File: network-ops.lisp
  ;;; Description:
  
  ;;; $Id: network-ops.lisp,v 1.14 2002/10/08 18:34:31 youngde Exp $
  
  (in-package "LISA")
  
  
negative.code:            (merge-root-node (new-root)
               (let ((existing-root
                      (find-root-node to-rete new-root)))
                 (cond ((null existing-root)
                        (add-new-root to-rete new-root))
                       (t
                        (add-node-set t existing-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)
  