anchor.diff:  (defun skip-expr-prefix-backward (line-buffer point)
     (skip-backward line-buffer point #'expr-prefix-char-p))
   
  -(defun skip-list-backward (line-buffer point)
  -  (loop :with count := 0 :do
  +(defun skip-list-backward (line-buffer point &optional (depth 0))
  +  (loop
       (decf point)
       (when (<= point 0)
  -      (return 0))
  +      (throw 'scan-error nil))
       (case (backward-syntax-type line-buffer point)
         ((:closed-paren)
  -       (incf count))
  +       (incf depth))
         ((:open-paren)
  -       (when (minusp (decf count))
  +       (when (minusp (decf depth))
            (return (1- point))))
         ((:string-quote)
          (setq point (skip-string-backward line-buffer point))))))
  
positive.code: 
  (defun forward-sexp-point (line-buffer point)
    (setq point (skip-space-forward line-buffer point))
    (skip-sexp-forward line-buffer point))
  
  (defun forward-sexp (arg key)
    (setq rl:*point*
  
negative.code: 
  (defun backward-sexp-point (line-buffer point)
    (setq point (skip-space-backward line-buffer point))
    (or (catch 'scan-error
          (skip-sexp-backward line-buffer point))
        point))
  
  (defun backward-sexp (arg key)
    (setq rl:*point*
  