anchor.diff:     (:register
       (:sequence (:greedy-repetition 0 nil (:inverted-char-class #\_))))
      (:greedy-repetition 2 2 #\_)))
  +
   (define-parse-tree-synonym
     strong-em-1
     (:sequence 
  
positive.code:    (:register
      (:sequence (:greedy-repetition 0 nil (:inverted-char-class #\_))))
     (:greedy-repetition 3 3 #\_)))
  (define-parse-tree-synonym
    strong-em-2 
    (:sequence 
  
negative.code:    (:register
      (:sequence (:greedy-repetition 0 nil (:inverted-char-class #\*))))
     (:greedy-repetition 2 2 #\*)))
  
  (define-parse-tree-synonym
    strong-2 
    (:sequence 
  