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Re: Quarterly appointments
Since the quarters have length (90 || 91), (91), (92), (92), the n-th
day of each quarter is
BYYEARDAY=$(n),$(-(92+92+91+1-n)),$(-(92+92+1-n)),$(-(92+1-n)),
for n in [1, 90]
You can't do
FREQ=QUARTERLY;BYDAY=2TU
in a single rule with freq=monthly and interval unless you're sure
that the n-th week falls in the first or last month of the quarter.
You can do it with multiple rrules though
FREQ=YEARLY;BYMONTH=1,2,3;BYDAY=2TU;BYSETPOS=1
FREQ=YEARLY;BYMONTH=4,5,6;BYDAY=2TU;BYSETPOS=1
FREQ=YEARLY;BYMONTH=7,8,9;BYDAY=2TU;BYSETPOS=1
FREQ=YEARLY;BYMONTH=10,11,12;BYDAY=2TU;BYSETPOS=1
The BYSETPOS should always have magnitude 1 but should have the same
sign as the BYDAY clause.
You can do intervals on quarters by filtering out some of the rules
and/or multiplying the set of rules and applying yearly intervals.
Handling multiple BYDAY clauses is going to require a set of RRULEs
per clause though.
On 10/04/07, Sander Koning <s.koning@xxxxxxxxxxx> wrote:
Hello,
I'm working on iCalendar import/export for the reservations module in
our product. So far, everything works quite fine, apart from the fact
that we support quarterly reservations. For example, "every second
Tuesday of each quarter" or "every 70th day of each odd quarter".
As iCalendar does not support FREQ=QUARTERLY, I will have to rewrite
these recurrence rules. Of course I can go and calculate everything
manually in my code, but that is bound to contain errors. So, if anybody
has got suggestions about how to tackle this, they would be most welcome.
If this is the wrong list to ask, then a pointer to the right place is
fine as well, of course.
Thanks in advance,
Cheers,
--
Sander Koning
TOPdesk Ontwikkeling
TOPdesk
Martinus Nijhofflaan 2, 2624 ES Delft
Postbus 559, 2600 AN Delft
T (015) 270 09 00
F (015) 257 52 56
W www.topdesk.nl