anchor.diff:          result))))
   
   (defun read-preserving-whitespace (&optional input-stream (eof-error-p t) eof-value recursive-p)
  -  (read-common (follow-stream-designator input-stream *standard-input*)
  +  (read-common (frob-input-stream input-stream)
                  eof-error-p
                  eof-value
                  recursive-p))
  
positive.code:     (:invert (if (upper-case-p c)
                   (char-downcase c)
                   (char-upcase c)))))
  
  (defun follow-stream-designator (stream default)
    (cond ((null stream) default)
          ((eql stream 't) *terminal-io*)
          ((streamp stream) stream)
          (t (error 'type-error
                    :expected-type '(or stream null (eql t))
                    :datum stream))))
  
  (defun whitespace[2]p (char &optional (readtable *readtable*))
    "Test if CHAR is a whitespace[2] character under READTABLE."
  
negative.code: 
  (defun read (&optional input-stream (eof-error-p t) eof-value recursive-p)
    "READ parses the printed representation of an object from STREAM and builds such an object."
    (let ((stream (frob-input-stream input-stream)))
      (with-stream-editor (stream recursive-p)
        (let ((result (read-common stream
                                   eof-error-p
  