anchor.diff:  
   
   (defun dll (&rest list)
  -  (let ((dlist (make-dll))
  -        (current nil))
  -    (map nil (lambda (item) (setf current (dll-append dlist current item))) list)
  -    dlist))
  +  (loop
  +     :with dlist = (make-dll)
  +     :for element :in list
  +     :for last-node = (dll-insert dlist nil element)
  +     :then (dll-insert dlist last-node element)
  +     :finally (return dlist)))
   
   (defun dll-first-node (dlist) (%dll-first dlist))
   (defun dll-last-node  (dlist) (%dll-last dlist))
  
positive.code: ;;;; -*- coding:utf-8 -*-
  ;;****************************************************************************
  ;;FILE:               dll.lisp
  ;;LANGUAGE:           Common-Lisp
  ;;SYSTEM:             Common-Lisp
  ;;USER-INTERFACE:     NONE
  ;;DESCRIPTION
  ;;    
  ;;    A doubly-linked list.
  ;;    
  ;;AUTHORS
  ;;    <PJB> Pascal J. Bourguignon <pjb@informatimago.com>
  ;;MODIFICATIONS
  ;;    2005-04-28 <PJB> Clean-up.
  ;;    2004-03-01 <PJB> Created.
  ;;BUGS
  ;;LEGAL
  ;;    GPL
  ;;    
  ;;    Copyright Pascal J. Bourguignon 2004 - 2005
  ;;    
  ;;    This program is free software; you can redistribute it and/or
  ;;    modify it under the terms of the GNU General Public License
  ;;    as published by the Free Software Foundation; either version
  ;;    2 of the License, or (at your option) any later version.
  ;;    
  ;;    This program is distributed in the hope that it will be
  ;;    useful, but WITHOUT ANY WARRANTY; without even the implied
  ;;    warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
  ;;    PURPOSE.  See the GNU General Public License for more details.
  ;;    
  ;;    You should have received a copy of the GNU General Public
  ;;    License along with this program; if not, write to the Free
  ;;    Software Foundation, Inc., 59 Temple Place, Suite 330,
  ;;    Boston, MA 02111-1307 USA
  ;;****************************************************************************
  
  (IN-PACKAGE "COMMON-LISP-USER")
  (DEFPACKAGE "COM.INFORMATIMAGO.COMMON-LISP.CESARUM.DLL"
  
negative.code: 
  (defun dll-insert (dlist node item)
    "
  DO:     Insert a new node after NODE, or before first position when (NULL NODE).
  RETURN: The new node.
  "
    (let ((new-node nil))
  