anchor.diff:  
   ;;; Text-style utilities
   
  -(defun merge-text-styles (s1 s2)
  +(defmethod merge-text-styles (s1 s2)
  +  (setq s1 (parse-text-style s1))
  +  (setq s2 (parse-text-style s2))
     (if (and (not (device-font-text-style-p s1))
   	   (not (device-font-text-style-p s2)))
         (let ((new-style (make-text-style (or (text-style-family s1)
  
positive.code: (defgeneric text-style-family (text-style))
  (defgeneric text-style-face (text-style))
  (defgeneric text-style-size (text-style))
  (defgeneric merge-text-style (text-style-1 text-style-2))
  (defgeneric text-style-ascent (text-style medium))
  (defgeneric text-style-descent (text-style medium))
  (defgeneric text-style-height (text-style medium))
  
negative.code: 					(or (text-style-size s1)
  					    (text-style-size s2)))))
  	(with-slots (size) new-style
  	  (case (text-style-size s1)
  	    (:smaller
  	     (setq size (find-smaller-size (text-style-size s2))))
  	    (:larger
  