anchor.diff:               stroke-linejoin
                stroke-miterlimit
                stroke-width
  +  style
                color
                color-interpolation
                color-rendering
  
positive.code:              color
               color-interpolation
               color-rendering
               externalResourcesRequired
               x1
               y1
               x2
               y2
               gradientUnits
               gradientTransform
               spreadMethod)
  
  (def-svg-tag metadata
               svg
  
negative.code: 
  (defmacro def-svg-tag-humpback (name &rest attributes)
    (let ((effective-attributes attributes))
    `(deftag ,(intern (string-upcase name)) (&attribute ,@(mapcar 
                                                            (lambda (attr)
                                                              (if (stringp attr) 
                                                                  (intern (string-upcase attr))
                                                                  attr))
                                                            effective-attributes)
                                                         &body body)
       (emit-open-tag ,name
                      (list ,@(mapcar (lambda (attr)
                                        `(cons 
  