anchor.diff:  	       (values reg t))))))))
   
   
  -
  +#+QNAMES
   (defmethod ensure-qname ((name string) (namespace string))
     "Ensure that the NAME is registered to a namespace denoted by
   STRING, within `*NAMESPACE-REGISTRY*'. Returns the simplified NAME
   and its contsining NAMESPACE object"
  -  ;; FIXME: "Elide *namespace-registry* to /dev/null"
     (let ((ns (ensure-namespace namespace *namespace-registry*)))
       (values (ensure-qname name ns)
   	    ns)))
  
positive.code:   (setf (namespace-registry-namespace-table instance)
  	...))
  
  
  (declaim (type namespace-registry *namespace-registry*))
  (defvar *namespace-registry*)
  
  (defun ensure-namespace (namespace registry)
  
negative.code:   (find prefix (namespace-prefix-table namespace)
  	:test #'string=))
  
  #+QNAMES
  (defstruct (qname
  	    (:constructor %make-qname (namespace name)))
    ;; FIXME: back-reference to a containing qname registry?
    (namespace "" :type simple-string)
    (name "" :type simple-string))
  
  #+QNAMES
  (defgeneric ensure-qname (name namespace)
    (:method ((name string) (namespace namespace))
      (values (%make-qname (namespace-string registry)
  