anchor.diff:     (char-before-2 char-before-3)
      (forward-list-1 backward-list-1)
      (skip-string-forward skip-string-backward)
  -   (skip-symbol-forward skip-symbol-backward))
  +   (skip-symbol-forward skip-symbol-backward)
  +   (next-char prev-char))
     (skip-space-forward)
     (let ((c (following-char)))
  -    (when (and
  -           (syntax-escape-char-p (preceding-char))
  -           (not (syntax-escape-char-p (char-before-2))))
  +    (when (escape-p (preceding-char) (char-before-2))
         (next-char 1)
         (setq c (following-char)))
       (cond
  
positive.code:     (do () (nil)
          (unless (next-char 1)
            (return))
        (unless (and (syntax-escape-char-p (preceding-char))
                  (not (syntax-escape-char-p (char-before-2))))
          (let ((c (following-char)))
            (cond
             ((eql c paren-char)
  
negative.code: (defun skip-until-closed-paren-backward ()
    (skip-chars-backward 'syntax-closed-paren-char-p t))
  
  (defun escape-p (before-1 before-2)
    (and (syntax-escape-char-p before-1)
         (not (syntax-escape-char-p before-2))))
  
  (define-dir-functions (forward-list-1 backward-list-1) ()
    ((skip-until-open-paren-forward skip-until-closed-paren-backward)
     (following-char preceding-char)
  