Re: [Evolution] Calendar: recurrence, exceptions and occurrences

[Dan Winship <danw ximian com>]

On Wed, 2004-03-03 at 10:33, D. D. Brierton wrote:
> Some classes, however (and more than you would perhaps think), are of
> this form: exactly four two-hour seminars to be taught, starting from
> this date. During the first class it then transpires that some of the
> students have exams on one of the subsequent weeks, and another class
> falls on a public holiday. The exceptions in this case should simply
> "push" the remaining appointments forward. I have, after all, specified
> that this appointment is to recur for four times exactly.

Sure, but you wouldn't just tell the students "because of conflicts, we
won't be meeting on day X". You'd explicitly say "but we will make up
the lost time by meeting on day Y" or something. The problem is that evo
doesn't let you make that clarification.

> I also have a non-work example -- I use Evo's appointments as an all
> purpose reminder/diary. Let's say, purely hypothetically, that I am one
> of those tremendously bad people who download American TV shows because
> I am too impatient to wait for them to air in the UK.

Heh. When I was an undergrad, we imported Babylon 5 episodes from the UK
for a season when the network here decided to be stupid and delay it 6
months. You guys have weird commercials. :-)

> In summary, I think that if you are using "until <date>" in your
> recurrence rule then an exception should indeed be a cancellation.
> However if you are using "for <n> occurrences" then an exception should
> be a postponement.

Well, I can come up with examples where that would be the wrong thing
too. In the university example, another professor might already have the
room booked during your time slot starting the week after your class was
supposed to end, so you have to switch the class to Mondays instead of
Wednesdays for the two "extra" weeks. In that case, an interface that
treated exceptions as postponements would be a pain to deal with, but
one that let you add and remove instances as you needed [which evo
doesn't completely do right now] would work fine.

-- Dan