anchor.diff:  
   (defun make-url (resource &optional mbid)
     "Generate the URL for a web service request."
  -  (format nil "~a~(~a~)~@[/~a~]"
  +  (format nil "~A~(~A~)~@[/~A~]"
             *base-url* resource mbid))
   
   (defun join-incs (incs)
     "Create a string representing all the incs."
  -  (format nil "~{~(~a~)~^+~}"
  +  (format nil "~{~(~A~)~^+~}"
             incs))
   ;;;; MusicBrainz resource interface.
   
  
positive.code:   "Current version of the package.")
  
  (defparameter *user-agent*
    (format nil "~(~a~)/~a" (package-name *package*) *version*)
    "User agent string sent to the server.")
  
  (defparameter *base-url* "http://musicbrainz.org/ws/2/"
  
negative.code: status of some incs may be optionally restricted.
  
  The second returned value is the function to call for the next page of results."
    (let ((args (list (cons (format nil "~(~A~)" filter-resource)
                            mbid)
                      (cons "limit" (format nil "~A" *ws-per-page*))
                      (cons "offset" (format nil "~A" (* page-offset *ws-per-page*))))))
      (when incs
        (push (cons "inc" (join-incs incs)) args))
      (when type
        (push (cons "type" (format nil "~(~A~)" type)) args))
      (when status
        (push (cons "status" (format nil "~(~A~)" status)) args))
      (values
        (ws-request (make-url resource)
                    args)
  