diff options
Diffstat (limited to 'module/vcomponent/timezone.scm')
| -rw-r--r-- | module/vcomponent/timezone.scm | 36 |
1 files changed, 35 insertions, 1 deletions
diff --git a/module/vcomponent/timezone.scm b/module/vcomponent/timezone.scm index f6112ebc..a89c8c5c 100644 --- a/module/vcomponent/timezone.scm +++ b/module/vcomponent/timezone.scm @@ -10,7 +10,7 @@ :use-module ((vcomponent datetime) :select (ev-time<?)) ) -;;@begin exampe +;;@begin example ;; <VTIMEZONE> :: "#<vcomponent 558c5da80fc0>" ;; TZID: Europe/Stockholm ;; X-LIC-LOCATION: Europe/Stockholm @@ -28,10 +28,44 @@ ;; : TZOFFSETFROM: +0200 ;; @end example +;;; GENERAL INFINITE EXTRAPOLATION OF TIMEZONE DATA IS IMPOSSIBLE, SINCE TIMEZONES +;;; DON'T CHANGE THAT PREDICTABLY + +;; @begin example +;; BEGIN:VTIMEZONE +;; TZID:Europe/Stockholm +;; BEGIN:STANDARD +;; DTSTART;VALUE=DATE-TIME:20181028T020000 +;; TZNAME:CET +;; TZOFFSETFROM:+0200 +;; TZOFFSETTO:+0100 +;; END:STANDARD +;; BEGIN:DAYLIGHT +;; DTSTART;VALUE=DATE-TIME:20190331T030000 +;; TZNAME:CEST +;; TZOFFSETFROM:+0100 +;; TZOFFSETTO:+0200 +;; END:DAYLIGHT +;; END:VTIMEZONE +;; @end example +;; This should really be parsed as: +;; STANDARD : [2018-10-28 02:00, 2019-03-31 03:00) +;; DAYLIGHT : [2019-03-21 03:00, ∞) + ;; Given a tz stream of length 2, takes the time difference between the DTSTART ;; of those two. And creates a new VTIMEZONE with that end time. ;; TODO set remaining properties, and type of the newly created component. (define (extrapolate-tz-stream strm) + (let ((nevent (copy-vcomponent (stream-car strm)))) + (set! (attr nevent 'DTSTART) + )) + + + ;; old code fails since (length standard) ≠ (length summer) + ;; Also, it copies the summmer time, making the alternation + ;; break (but that wasn't the primary problem) + + #; (let ((nevent (copy-vcomponent (stream-ref strm 1)))) (mod! (attr nevent 'DTSTART) = (add-duration (time-difference |