+ (lurk-display-string
+ nil
+ (propertize lurk-error-prefix 'face 'lurk-error)
+ (apply #'concat messages)))
+
+(defun lurk-highlight-context (context)
+ (maphash
+ (lambda (this-context facelist)
+ (if (equal this-context context)
+ (setcar facelist 'lurk-text)
+ (setcar facelist 'lurk-faded)))
+ lurk-context-facelists)
+ (force-window-update "*lurk*"))
+
+(defun lurk-zoom-in (context)
+ (with-current-buffer "*lurk*"
+ (maphash
+ (lambda (this-context _)
+ (when this-context
+ (let ((this-context-atom (intern this-context)))
+ (if (equal this-context context)
+ (remove-from-invisibility-spec this-context-atom)
+ (add-to-invisibility-spec this-context-atom)))))
+ lurk-context-facelists)
+ (force-window-update "*lurk*")))
+
+(defun lurk-zoom-out ()
+ (with-current-buffer "*lurk*"
+ (maphash
+ (lambda (this-context _)
+ (let ((this-context-atom (if this-context (intern this-context) nil)))
+ (remove-from-invisibility-spec this-context-atom)))
+ lurk-context-facelists)
+ (force-window-update "*lurk*")))
+
+(defconst lurk-url-regex
+ (rx (:
+ (group (+ alpha))
+ "://"
+ (group (or (+ (any alnum "." "-"))
+ (+ (any alnum ":"))))
+ (opt (group (: ":" (+ digit))))
+ (opt (group (: "/"
+ (opt
+ (* (any alnum "-/.,#:%=&_?~@+"))
+ (any alnum "-/#:%=&_~@+")))))))
+ "Imperfect regex used to find URLs in plain text.")
+
+(defun lurk-click-url (button)
+ (browse-url (button-get button 'url)))
+
+(defun lurk-buttonify-urls (&rest strings)
+ "Turn substrings which look like urls in STRING into clickable buttons."
+ (with-temp-buffer
+ (apply #'insert strings)
+ (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)))
+
+(defun lurk-add-formatting (string)
+ (with-temp-buffer
+ (insert string)
+ (goto-char (point-min))
+ (let ((bold nil)
+ (italics nil)
+ (underline nil)
+ (strikethrough nil)
+ (prev-point (point)))
+ (while (re-search-forward (rx (any "\x02\x1D\x1F\x1E")) nil t)
+ (let ((beg (+ (match-beginning 0) 1)))
+ (if bold
+ (add-face-text-property prev-point beg '(:weight bold)))
+ (if italics
+ (add-face-text-property prev-point beg '(:slant italic)))
+ (if underline
+ (add-face-text-property prev-point beg '(:underline t)))
+ (if strikethrough
+ (add-face-text-property prev-point beg '(:strike-through t)))
+ (pcase (match-string 0)
+ ("\x02" (setq bold (not bold)))
+ ("\x1D" (setq italics (not italics)))
+ ("\x1F" (setq underline (not underline)))
+ ("\x1E" (setq strikethrough (not strikethrough))))
+ (delete-region (match-beginning 0) (match-end 0))
+ (setq prev-point (point)))))
+ (buffer-string)))
+