run emacs diary if idle and we're on a new day

dat-diary-idle-timer.lisp

(defvar dat-diary-idle-timer
  ;; day of week
  (let ((dat-ran-diary-on-day -1)
	(idle-sec 600))
    (run-with-idle-timer
     idle-sec
     t
     #'(lambda ()
	 ;; check if we've run diary yet today
	 (let ((day-number (calendar-day-of-week (calendar-current-date)))))
	 (when (not (= (dat-ran-diary-on-day)
		       day-number))
	   (setf dat-ran-diary-on-day day-number)
	   (diary))))))