anchor.diff:          (curvalue (value current)))
       (cond ((< newvalue curvalue)
              (if (null (left current))
  -               (progn
  -                 (setf (left current) n)
  -                 (setf (parent n) current))
  +               (setf (left current) n (parent n) current)
                (insert-rec (left current) n)))
             ((> newvalue curvalue)
              (if (null (right current))
  -               (progn
  -                 (setf (right current) n)
  -                 (setf (parent n) current))
  +               (setf (right current) n (parent n) current)
                (insert-rec (right current) n)))
             (t nil))) ; no duplicates allowed
     T)
  
positive.code:       (if (null delnode)
            nil ; No node with 'value' found.
          (let ((par (parent delnode)))
            (progn
              (cond ((eql value (value (root tree))) 
                     (deleteInternalNode (root tree)))
                    ((and 
  
negative.code:                     (not (null (right delnode))))
                     (deleteInternalNode delnode))
                    (T (deleteNode delnode)))
              (decf (size tree))))))
    T
  )
  
  