Toggle Org Emphasis with the Marker Itself

I recently read an Irreal post about org-emphasize. It reminded me of a small command I have used for a long time: when a region is active, the * key toggles bold emphasis instead of merely inserting a character.

The interaction is simple:

|text|     + *  →  *text*
|*text*|   + *  →  text
*|text|*   + *  →  text

Without an active region, * behaves normally.

(defun my/org-toggle-emphasis (char)
  "Toggle emphasis CHAR around the region, or insert CHAR normally."
  (if (not (use-region-p))
      (let ((last-command-event char))
        (org-self-insert-command 1))
    (let ((beg (region-beginning))
          (end (region-end)))
      (cond
       ((and (>= (- end beg) 2)
             (eq (char-after beg) char)
             (eq (char-before end) char))
        (save-excursion
          (goto-char end)
          (delete-char -1)
          (goto-char beg)
          (delete-char 1)))
       ((and (> beg (point-min))
             (< end (point-max))
             (eq (char-before beg) char)
             (eq (char-after end) char))
        (save-excursion
          (goto-char end)
          (delete-char 1)
          (goto-char beg)
          (delete-char -1)))
       (t
        (org-emphasize char))))))

(defun my/org-make-toggle (char)
  "Return an interactive Org emphasis toggle for CHAR."
  (lambda ()
    (interactive)
    (my/org-toggle-emphasis char)))

(define-key org-mode-map (kbd "*") (my/org-make-toggle ?*))

This resembles how electric pairs can surround a selected region, but electric-pair-mode does not provide the removal part of the toggle. Using org-emphasize directly keeps the implementation self-contained and leaves the rest of Org’s pairing behavior unchanged.

The same helper can also be bound to /, _, +, =, or ~.