Format mails for interleaved response in emacs

format_mails.el

(defun sha/format-mail-header ()
  (interactive)
  (with-current-buffer (current-buffer)
    (let ((beg (region-beginning))
          (end (region-end))
          (fill-column 60))
      (goto-char beg)
      (insert "Hi,\n\n")
      (forward-line 0)
      (insert "---")
      (end-of-line)
      (newline)
      (fill-individual-paragraphs (point) end)
      (goto-char (+ 5 beg))
      (forward-line)
      (while (<= (point) (+ 3 1 (count-lines beg end) end))
        (insert "| ")
        (forward-line))
      (insert "\\--\n\n"))))

(defun sha/format-mail-interleave ()
  (interactive)
  (with-current-buffer (current-buffer)
    (let ((beg (region-beginning))
          (end (region-end))
          (fill-column 60))
      (goto-char beg)
      (forward-line 0)
      (newline)
      (insert "---")
      (newline)
      (goto-char end)
      (end-of-line)
      (newline)
      (goto-char (+ beg 3 2))
      (fill-individual-paragraphs (point) end)
      (while (<= (point) (+ 1 3 1 (count-lines beg end) end))
        (insert "| ")
        (forward-line))
      (insert "\\--\n\n"))))