anchor.diff:    (with-slots (recording-p drawing-p) stream
       (let ((old-record recording-p)
             (old-draw drawing-p))
  +      (unless (eq old-record record)
  +        (stream-close-text-output-record stream))
         (unwind-protect
              (progn
                (setq recording-p record
  
positive.code: ;;;  (c) copyright 2001 by 
  ;;;           Arnaud Rouanet (rouanet@emi.u-bordeaux.fr)
  ;;;           Lionel Salabartan (salabart@emi.u-bordeaux.fr)
  
  ;;; This library is free software; you can redistribute it and/or
  ;;; modify it under the terms of the GNU Library General Public
  
negative.code:                                           continuation record-type
                                            &rest initargs
                                            &key parent)
    (stream-close-text-output-record stream)
    (unless parent
      (setq parent (stream-current-output-record stream)))
    (let ((new-record (apply #'make-instance record-type :parent parent initargs))
  