for comment

insert-delete-char-at-beginning.el

(defun me-insert-delete-char-at-beginning (begin-pos end-pos c)
	"insert or delete c at beginning of every line"
	(save-excursion
		(goto-char begin-pos)
		(move-beginning-of-line nil)
		(let ((line-num-begin (line-number-at-pos begin-pos))
					(line-num-end (line-number-at-pos end-pos))
					(delete (eq c (char-after (point)))))
			(while (<= line-num-begin line-num-end)
				;; set delete for insert flag base on first line
				(if delete
						(progn
							(delete-char 1 nil)
							;; for case beginning don't have 2 ?c
							(when (eq c (char-after (point)))
								(delete-char 1 nil)))
					(self-insert-command 2 c))
				(next-line)
				(move-beginning-of-line nil)
				(setq line-num-begin (1+ line-num-begin)))))
	(me-advice-clear-everything))