+;;; URL buttons
+
+(defconst lurk-url-regex
+ (rx (:
+ (group (+ alpha))
+ "://"
+ (group (or (+ (any alnum "." "-"))
+ (+ (any alnum ":"))))
+ (opt (group (: ":" (+ digit))))
+ (opt (group (: "/"
+ (opt
+ (* (any alnum ",.-~/@|:%#=&_"))
+ (+ (any alnum "-~/@|:%#=&")))))))))
+
+(defun lurk-click-url (button)
+ (browse-url (button-get button 'url)))
+
+(defun lurk-buttonify-urls (string)
+ "Turn substrings which look like urls in STRING into clickable buttons."
+ (with-temp-buffer
+ (insert string)
+ (goto-char (point-min))
+ (while (re-search-forward lurk-url-regex nil t)
+ (let ((url (match-string 0)))
+ (make-text-button (match-beginning 0)
+ (match-end 0)
+ 'action #'lurk-click-url
+ 'url url
+ 'follow-link t
+ 'face 'button
+ 'help-echo "Open URL in browser.")))
+ (buffer-string)))
+