Function: decoded-time--alter-day

decoded-time--alter-day is a byte-compiled function defined in time-date.el.gz.

Signature

(decoded-time--alter-day TIME INCREASE)

Documentation

Increase or decrease the day in TIME by 1.

Source Code

;; Defined in /usr/src/emacs/lisp/calendar/time-date.el.gz
(defun decoded-time--alter-day (time increase)
  "Increase or decrease the day in TIME by 1."
  (if increase
      (progn
        (incf (decoded-time-day time))
        (when (> (decoded-time-day time)
                 (date-days-in-month (decoded-time-year time)
                                     (decoded-time-month time)))
          (setf (decoded-time-day time) 1)
          (decoded-time--alter-month time t)))
    (decf (decoded-time-day time))
    (when (zerop (decoded-time-day time))
      (decoded-time--alter-month time nil)
      (setf (decoded-time-day time)
            (date-days-in-month (decoded-time-year time)
                                (decoded-time-month time))))))