[Cosmo-dev] Recurrence modifications, filters, and diffs

[Jeffrey Harris]

Hi Randy and Brian,

In Chandler (and Cosmo's UI) we treat modifications as inheriting
attributes from the master event.  So if a modification changes the
SUMMARY, the modification's VEVENT representation doesn't need to
include the DESCRIPTION from the master, it's just inherited.

In EIM I'd like modifications to be sent around having no value for a
field if it's inherited from the master.

This is a little problematic for start time and end time, since we're
storing things in icalendar.  icalendar modifications require a start
time and really an end time is required for interop.

I'd like the conversion to/from icalendar from/to EventModification
records to handle no value in modifications smoothly.  I think this means:

- Putting a DTSTART and a DTEND into icalendar even if they weren't changed
- NOT putting DTSTART and DTEND into EIM unless start time or duration
was changed by the modification

Finally, I think we need a third (or a forth?) kind of null value for
EIM, there's already empty string vs. empty record vs. No Change, this
is "no attribute modification", or inherit from the master.

Does that all make sense?  Is it doable?

Sincerely,
Jeffrey