anchor.diff:              (pov-directive-name object)
               (pov-directive-value object))))
   
  +(defmethod object-rope ((object pov-directive))
  +  (with-pov-indent old-indent
  +    (declare (ignore old-indent))
  +    (rope '|#| (pov-directive-type object) '| |
  +          (pov-directive-name object)
  +          '| = |
  +          (object-rope (pov-directive-value object)))))
   
   (defstruct (pov-include (:constructor pov-include (file)))
     file)
  
positive.code:   (format stream "~&#include ~S"
            (pov-include-file object)))
  
  (defstruct (pov-sequence (:constructor pov-sequence (statements)))
    statements)
  
  (defmethod print-object ((object pov-sequence) stream)
    (loop for x in (pov-sequence-statements object)
       do (print-object x stream)))
  
  (defun pov-quality (float-quality)
    "Return numeric povray quality for proportional to RATIO.
  
negative.code:           *pov-indent*
            (pov-value-value object)))
  
  (defmethod object-rope ((object pov-value))
    (rope  (format nil "~A" (pov-value-value object))))
  
  (defstruct (pov-block (:constructor pov-block (name list)))
    name
  