anchor.diff:        (type-error :expected-type 'ncname :datum prefix))
       (unless (cxml::valid-ncname-p name)
         (type-error :expected-type 'ncname :datum name))
  -    ;; FIXME: define RESOLVE-PREFIX-NAMESPACE
       (let ((ns (resolve-prefix-namespace prefix registry)))
         (unless ns
  -	(error "Prefix ~s is not registered in ~s" prefix registry))
  +	(error 'prefix-not-found-error
  +	       :name prefix
  +	       :namespace registry))
         (values (ensure-qname-string name ns)
  -	      ns))))+	      ns))))
  
positive.code: 		 (return (values ns nil))))))
        (or (find-registered)
  	  (cond
  	  	((and ensure-p (instance-finalized-p registry)
  	     (error "Unable to create instance for namespace ~s in ~
  finalized registry ~s"
  		    namespace registry))
  	    (ensure-p
  	     (let ((reg (make-namespace the-string)))
  	       (vector-push-extend reg table)
  	       (values reg t))))
  	     (t (error "Namespace ~s not found in registry ~s ~
  when :ENSURE-P NIL"
  	     		namespace registry))
  	       ))))
  
  
  (define-condition namespace-condition ()
    ((namespace
      :initarg :namespace
      :reader namespace-condition-namespace)))
  
  (define-condition namespace-prefix-condition (namespace-condition)
    ((prefix
      :initarg :prefix
      :reader prefix-condition-prefix)))
  
  (defmethod print-object ((instance namespace-prefix-condition) stream)
    (print-unreadable-object (instance stream :type t :identity t)
      (write-string (prefix-condition-prefix instance) stream)
      (write-char #\Space stream)
      (let ((ns (namespace-condition-namespace instance)))
        (typecase ns
  
negative.code: 	ns-p pf-p)
      (do-vector (ns namespaces (cond
  				(errorp
  				 (error 'prefix-not-found-error
  					:name  prefix
  					:namespace registry))
  				(t (values nil nil))))
        (declare (type namespace ns))
        (let ((p (find-prefix prefix ns)))
  