Function: icalendar-recur-refine-byhour

icalendar-recur-refine-byhour is a byte-compiled function defined in icalendar-recur.el.gz.

Signature

(icalendar-recur-refine-byhour INTERVAL HOURS &optional VTIMEZONE)

Documentation

Resolve INTERVAL into a list of subintervals matching HOURS.

HOURS should be a list of values from a recurrence rule's BYHOUR=... clause; see icalendar-recur for the possible values.

Source Code

;; Defined in /usr/src/emacs/lisp/calendar/icalendar-recur.el.gz
(defun icr:refine-byhour (interval hours &optional vtimezone)
  "Resolve INTERVAL into a list of subintervals matching HOURS.

HOURS should be a list of values from a recurrence rule's
BYHOUR=... clause; see `icalendar-recur' for the possible values."
  (let* ((sorted-hours (sort hours))
         (interval-start (icr:interval-low interval))
         (interval-end (icr:interval-high interval))
         (curr-dt interval-start)
         (subintervals nil))
    (while curr-dt
      ;; For each day in the interval...
      (dolist (h sorted-hours)
        ;; ...the subinterval is one hour long in the given hour
        (let* ((low (ical:date-time-variant curr-dt
                                            :hour h :minute 0 :second 0
                                            :tz vtimezone))
               (high (ical:date/time-add low :hour 1 vtimezone)))
          (ignore-errors ; do not generate subintervals for nonexistent times
            (when (ical:date/time< low curr-dt)
              (setq low curr-dt))
            (when (ical:date/time< interval-end high)
              (setq high interval-end))
            (when (and (ical:date/time<= interval-start low)
                       (ical:date/time< low high)
                       (ical:date/time<= high interval-end))
              (push (icr:make-interval low high) subintervals)))))
      (setq curr-dt (ical:date/time-add curr-dt :day 1 vtimezone))
      (when (ical:date-time<= interval-end curr-dt)
        ;; we're done:
        (setq curr-dt nil)))
    (nreverse subintervals)))