Xah Talk Show 2025-03-21 Ep631 emacs lisp coding html insert doctype

https://youtu.be/9lKmSM18B2E
(defun xah-html-insert-doctype ()
  "Insert a html doctype.
if `universal-argument' is called first, prompt select a doctype from choices.
Created: 2025-03-21
Version: 2025-03-21"
  (interactive)
  (if current-prefix-arg
      (let (xdoctype
            (xmenu
             '("<!DOCTYPE html>"
               "<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01 Transitional//EN\" \"http://www.w3.org/TR/html4/loose.dtd\">"
               "<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01//EN\" \"http://www.w3.org/TR/html4/strict.dtd\">"
               "<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01 Frameset//EN\" \"http://www.w3.org/TR/html4/frameset.dtd\">"
               "<!DOCTYPE html PUBLIC \"-//W3C//DTD XHTML 1.0 Transitional//EN\" \"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd\">"
               )))
        (setq xdoctype (completing-read "pick one:" xmenu nil t))
        (insert xdoctype))
    (insert "<!DOCTYPE html>")))