anchor.diff:  
   
   ;; Copyright (c) 2002-2005, Edward Marco Baringer
  -;; All rights reserved. 
  -;; 
  +;; All rights reserved.
  +;;
   ;; Redistribution and use in source and binary forms, with or without
   ;; modification, are permitted provided that the following conditions are
   ;; met:
  -;; 
  +;;
   ;;  - Redistributions of source code must retain the above copyright
   ;;    notice, this list of conditions and the following disclaimer.
  -;; 
  +;;
   ;;  - Redistributions in binary form must reproduce the above copyright
   ;;    notice, this list of conditions and the following disclaimer in the
   ;;    documentation and/or other materials provided with the distribution.
  
positive.code: ;;  - Neither the name of Edward Marco Baringer, nor BESE, nor the names
  ;;    of its contributors may be used to endorse or promote products
  ;;    derived from this software without specific prior written permission.
  ;; 
  ;; THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  ;; "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  ;; LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  
negative.code:   (iter (for (k v . rest) on env by #'cddr)
  	(collect k into keys)
  	(collect v into values)
  	(finally
  	 (progv keys values
  	   ;; pass env to funcall to assist debugging
  	   (return (funcall tal-fn env))
  