Recurence support is partial

[RyanGibb]

The recurrence support added in #308 is partial. A small example, repeating UNTIL a date is unsupported -- repeating events will continue forever.

The iCalendar RFC defines recurring events in detail in these sections.

Though, I'm not sure if this is possible or wise to do in org-mode. It seems org-mode recommends just enumerating all dates for an event repeating until a certain date, which could cause difficulties syncing.

Discussions in #216 implementing this upstream in org-mode's ox-icalendar, but the bidirectional requirements of org-caldav seem quite distinct from this exporter.

Any suggestions for how I might go about implementing this would be greatly appreciated.

[jeffvalk]

I'm not an expert in the RFC, but I believe the two relevant rules are COUNT and UNTIL, which are optional and mutually exclusive.

I'm also not an expert in org-caldav 🙂, but I would think that in the simplest case, it would be possible to parse these and add them to a property drawer, so that they could be used in a org-agenda-skip-function. This would leave the date math to the user, but at least the data to perform it would be available, which it currently isn't. A far more helpful approach would calculate whether the recurrence rule should expire the event, and indicate this somehow -- again, perhaps in the property drawer.

Thank you for bringing this up! Showing every repeating event as continuing indefinitely is...not ideal.

[RyanGibb]

I had a go at getting something working, but it seems org mode isn't as expressive as the ics file format, so I've written a client for Emacs which others running into limitations of org-caldav might find useful https://github.com/RyanGibb/caledonia

[artelse]

@RyanGibb With Caledonia, do you intend integration with org-agenda? (And yes, repeating events going on forever is annoying as I like to keep my original agenda history intact.)

[RyanGibb]

I think a distinct interface affords more flexibility, but in the future integration with org-agenda could be interesting. I don't want to pollute org-caldav's issue board with discussion of this project though so feel free to open an issue on Caledonia!