anchor.diff:    
   (defun null-pointer-p (pointer)
     (zerop (sap-int pointer)))
  -
  +  
   
   (defmacro when-bind ((var expr) &body body)
     `(let ((,var ,expr))
  
positive.code: ;; License along with this library; if not, write to the Free Software
  ;; Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  
  ;; $Id: gutils.lisp,v 1.3 2000-10-05 17:18:28 espen Exp $
  
  
  (in-package "KERNEL")
  
negative.code:       (fdefinition object)
      object))
  
  
  (defun split-string (string delimiter)
    (declare (simple-string string) (character delimiter))
    (check-type string string)
    (check-type delimiter character)
    (let ((pos (position delimiter string)))
     (if (not pos)
          (list string)
        (cons
         (subseq string 0 pos)
         (split-string (subseq string (1+ pos)) delimiter)))))
  
  (defun split-string-if (string predicate)
    (declare (simple-string string))
    (check-type string string)
    (check-type predicate (or symbol function))
    (let ((pos (position-if predicate string :start 1)))
      (if (not pos)
          (list string)
        (cons
         (subseq string 0 pos)
         (split-string-if (subseq string pos) predicate)))))
  
  (defun concatenate-strings (strings &optional delimiter)
    (if (not (rest strings))
        (first strings)
      (concatenate
       'string
       (first strings)
       (if delimiter (string delimiter) "")
       (concatenate-strings (rest strings)))))
  