anchor.diff:                                  :if-does-not-exist :create
                                   :if-exists :supersede
                                   :external-format external-format-out)
  -      (loop for line = (read-line in nil nil)
  -            while line do (write-line line out)))))
  +      (loop :for line := (read-line in nil nil)
  +            :while line :do (write-line line out)))))
   
   (defun ef-name (ef)
     (format nil "~A ~A"
  
positive.code: ;;; and the cdr is the corresponding external format.  This list
  ;;; contains all possible line-end conversions.
  (defun create-file-variants (file-name symbol)
    (loop for eol-style in '(:lf :cr :crlf) collect
          (cons (format nil "~A_~(~A~)_~(~A~).txt"
                        file-name symbol eol-style)
                (babel:make-external-format symbol eol-style))))
  
negative.code:   (with-open-file (stream1 file1 :element-type '(unsigned-byte 8))
      (with-open-file (stream2 file2 :element-type '(unsigned-byte 8))
        (and (= (file-length stream1) (file-length stream2))
             (loop :for byte1 := (read-byte stream1 nil nil)
                   :for byte2 := (read-byte stream2 nil nil)
                   :while (and byte1 byte2)
                   :always (= byte1 byte2))))))
  
  ;;; Copies the contents of the file denoted by the pathname PATH-IN to
  ;;; the file denoted by the pathname PATH-OUT using flexi streams -
  