[Evolution] Calendar: recurrence, exceptions and occurrences

["D. D. Brierton" <darren dzr-web com>]

I've just been adding some recurring appointments, and noticed something
that struck me as odd. Say I am contracted to teach exactly four
classes, and the time will be a Wednesday, at the same time, but there
will be two weeks after the first class when the class won't be able to
take place.

I create an appointment, go to the "Recurrence" tab, and select "Simple
recurrence" for "Recurrence Rule", and select "Every 1 week(s) on W for
4 occurrences".

Then, under "Exceptions" I add the two dates on which the class won't
take place.

Result: only two classes are added to my calendar. It seems the
"exceptions" count as "occurrences". In order to achieve exactly what I
want I have to change the "Recurrence Rule" to ""Every 1 week(s) on W
for 6 occurrences". This strikes me as very counter-intuitive. If it
turns out that another Wednesday becomes unavailable for the class, or
that one of the Wednesdays that was originally unavailable becomes
available, in order to adjust my calendar I have to change the
recurrence tab in two places: I have to change the exceptions and also
the occurrences.

To me an occurrence and an exception are semantically exclusive: if an
event is scheduled to recur over a five week period with the exception
of one week in the middle then it occurs four times, not five.

Is there some reason for this behaviour? I am assuming that there might
be, although I can't guess what, because I've noticed that Mozilla
Calendar behaves exactly the same way. Am I alone in finding this
bizarre?

Best, Darren

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D. D. Brierton            darren dzr-web com          www.dzr-web.com
       Trying is the first step towards failure (Homer Simpson)
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