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