anchor.diff:  (defgeneric appender-stream (appender) 
     (:documentation "Should return the stream to which appender will write log messages"))
   
  -(defclass fixed-stream-appender (stream-appender)
  +(defclass fixed-stream-appender-base (stream-appender)
  +  ((stream :accessor appender-stream))
  +  (:documentation "Appender that writes message to the stream in STREAM slot"))
  +
  +(defclass fixed-stream-appender (fixed-stream-appender-base)
     ((stream :initarg :stream :accessor appender-stream))
  -  (:documentation "Appender that writes message to the stream specified in STREAM slot"))
  +  (:documentation "Appender that writes message to the stream in STREAM slot"))
   
   (defclass console-appender (stream-appender) () 
     (:documentation "A stream appender that writes messages to
  
positive.code:   (values))
  
  ;; Save one generic function dispatch by accessing STREAM slot directly
  (defmethod appender-do-append ((this fixed-stream-appender)
                                 logger
  			       level
                                 log-func)
  
negative.code:     (close (slot-value appender 'stream))
      (slot-makunbound appender 'stream)))
  
  (defclass file-appender-base (fixed-stream-appender-base) () 
    (:documentation "Appender that writes to a file and closes it when
  its no longer attached to loggers"))
  
  