anchor.diff:    (remf-keywords args :external-format)
     `(with-open-file (,stream-name ,file-name :direction :output
                       ,@(when external-format
  -                        `(:external-format ,(encoding-keyword-to-native external-format)))
  +                        `(:external-format
  +                          ,(if (keywordp external-format)
  +                               `(encoding-keyword-to-native ,external-format)
  +                               external-format)))
                       ,@args)
        ,@body))
   
  
positive.code:   (remf-keywords args :external-format)
    `(with-open-file (,stream-name ,file-name :direction :input
                      ,@(when external-format
                          `(:external-format ,(encoding-keyword-to-native external-format)))
                      ,@args)
       ,@body))
  
  
negative.code: 
  The file specified by PATHNAME will be read one ELEMENT-TYPE
  element at a time, the EXTERNAL-FORMAT and ELEMENT-TYPEs must be
  compatible.
  
  The EXTERNAL-FORMAT parameter will be passed to
  ENCODING-KEYWORD-TO-NATIVE, see ENCODING-KEYWORD-TO-NATIVE to
  possible values."
    (with-input-from-file
        (file-stream pathname :external-format (encoding-keyword-to-native external-format))
      (with-output-to-string (datum) 
        (let ((buffer (make-array buffer-size :element-type element-type)))
  	(loop for bytes-read = (read-sequence buffer file-stream)
  	      do (write-sequence buffer datum :start 0 :end bytes-read)
  	      while (= bytes-read buffer-size))))))
  
  (defun write-string-to-file (string pathname &key (if-exists :error)
                                                    (if-does-not-exist :error)
                                                    (external-format :us-ascii))
    "Write STRING to PATHNAME.
  
  The EXTERNAL-FORMAT parameter will be passed to
  ENCODING-KEYWORD-TO-NATIVE, see ENCODING-KEYWORD-TO-NATIVE to
  possible values."
    (with-output-to-file (file-stream pathname :if-exists if-exists
                                      :if-does-not-exist if-does-not-exist
                                      :external-format (encoding-keyword-to-native external-format))
      (write-sequence string file-stream)))
  
  (defun copy-file (from to &key (if-to-exists :supersede)
  