anchor.diff:    expr-prefix-backward-function
     line-comment-string
     block-comment-pairs
  +  block-string-pairs
     region-list
     match-list)
   
  
positive.code:               (:fence
                 #1#)
                (:block-comment
                 (let ((regex (%create-pair-regex block-comment-pair)))
                   (loop
                     (unless (search-forward-regexp p regex to)
                       (move-point p to)
                       (return-from outer))
                     (cond
                       ((match-string-at p (cdr block-comment-pair))
                        (character-offset p (length (car block-comment-pair)))
                        (when (= 0 (decf block-comment-depth))
                          (setf block-comment-depth nil)
                          (setf block-comment-pair nil)
                          (setf type nil)
                          (setf token-start-point nil)
                          (return p)))
                       (t
                        (character-offset p (length (cdr block-comment-pair)))
                        (incf block-comment-depth))))))
                (:line-comment
                 (when (and (point<= p to)
  
negative.code:              (%skip-list-forward point 0))
              ((syntax-closed-paren-char-p c)
               nil)
              ((multiple-value-setq (n pair) (syntax-start-block-string-p point))
               (character-offset point n)
               (if (search-forward point (cdr pair))
                   point
                   nil))
              ((syntax-string-quote-char-p c)
               (%skip-string-forward point))
              ((syntax-fence-char-p c)
  