anchor.diff:  
   (defun format (stream string-or-fn &rest args)
     (cond ((stringp stream)
  -         (cl:format stream "~A"
  -                      (with-output-to-string (stream)
  -                        (apply #'format stream string-or-fn args)))
  +         (apply #'format (make-instance 'sys.int::string-output-stream
  +                                        :element-type 'character
  +                                        :string stream)
  +                string-or-fn args)
            nil)
           ((null stream)
            (with-output-to-string (stream)
  
positive.code: (defun compile-format (start end)
    (let ((result nil))
      (prog (c i j fn)
       L(multiple-value-setf (c i j) (next-directive start end))
        (when (if (null c) (< start end) (< start i))
          (push (literal start (if i i end)) result))
        (when (null c) (return (nreverse result)))
  
negative.code: ;reported in a file without stopping the compilation of the file.
  
  (defun maybe-compile-format-string (string force-fn?)
    (if (not (or force-fn? (fancy-directives-p string)))
        string
        (eval `(formatter ,string))))
  
  ;COMPILE-FORMAT gets called to turn a bit of format control string into code.
  