anchor.diff:    (cond ((eq reserved-name nil)       *standard-readtable*)
   	((eq reserved-name :standard) *standard-readtable*)
   	((eq reserved-name :current)  *readtable*)
  -	(t (error "No such reserved readtable: ~S" reserved-name))))
  +	(t (error "Bug: no such reserved readtable: ~S" reserved-name))))
   
   (defun find-readtable (named-readtable-designator)
     "Looks for the readtable specified by NAMED-READTABLE-DESIGNATOR and 
  
positive.code:   (symbol-macrolet ((designator named-readtable-designator))
      (cond ((find-readtable designator))
  	  ((not default-p)
  	   (error "The name ~S does not designate any readtable." designator))
  	  (t (setf (find-readtable designator) (ensure-readtable default))))))
  
  
negative.code: (define-condition readtable-does-not-exist (readtable-error)
    ((readtable-name :initarg :readtable-name 
  	           :initform (required-argument)
  	           :accessor missing-readtable-name
                     :type named-readtable-designatord))
    (:report (lambda (condition stream)
               (format stream "A readtable named ~S does not exist."
                       (missing-readtable-name condition)))))
  
  (define-condition readtable-does-already-exist (readtable-error)
    ((readtable-name :initarg :readtable-name
                     :initform (required-argument)
                     :accessor existing-readtable-name
                     :type named-readtable-designatord))
    (:report (lambda (condition stream)
               (format stream "A readtable named ~S already exists."
                       (existing-readtable-name condition)))))
  
  
  