anchor.diff:                        (digit-char-p (car minor-digits) 10)))
          (pop minor-digits))))
   
  +(defun make-ratio (sign numerator-digits denominator-digits)
  +  (let ((numerator (make-integer sign numerator-digits *read-base*))
  +        (denominator (make-integer #\+ denominator-digits *read-base*)))
  +    ;; For now we do not support ratios.  We just convert them into
  +    ;; floats.
  +    (/ (* numerator 1.0)
  +       (* denominator 1.0))))
  +
   (defun maybe-eat-sign (token)
     (cond ((signp (car token))
            (values (car token)
  
positive.code:       (float-token-method-2-p token)))
  
  (defun ratio-token-p (token)
    (declare (ignore token))
    ;; TODO implement ratios
    (error "implement me!"))
  
  (defun numeric-token-p (token)
    ;; http://www.lispworks.com/documentation/HyperSpec/Body/02_ca.htm
    (or (integer-token-p token)
        (float-token-p token)
        ;; TODO implement ratios
        #+nil(ratio-token-p token)))
  
  (defun symbol-token-p (token)
    ;; http://www.lispworks.com/documentation/HyperSpec/Body/02_cd.htm
  
negative.code: (defun exponent-marker-p (char)
    (member 'exponent-marker (char-traits char)))
  
  (defun ratio-marker-p (char)
    (member 'ratio-marker (char-traits char)))
  
  (defun invalidp (char)
    (member 'invalid (char-traits char)))
  
  