[Ietf-calsify] summary of jabber sessions and confirmation of issues

[Reinhold Kainhofer]

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

Am Mittwoch, 11. Oktober 2006 18:03 schrieben Sie:
> Hi Reinhold,
>
> --On October 11, 2006 5:50:22 PM +0200 Reinhold Kainhofer
>
> <reinhold at kainhofer.com> wrote:
> >> An instance representing the supplied DTSTART value is always present as
> >> per 4.8.5.4 (which says in the Description paragraph: 'The "DTSTART"
> >> property defines the first instance in the recurrence set.'). So a
> >> COUNT=1 will only ever generate the DTSTART instance. So your
> >> 'intuitive' expectation is wrong.
> >
> > On the other hand, section 4.8.5.2 about EXRULE (and section 4.8.5.1
> > about  EXDATE) says that the EXRULE/EXDATE properties can be used to
> > exlude the  DTSTART. Notice the word *can* and "in such cases", which
> > indicate that the  DTSTART is not always automatically generated by an
> > EXRULE.
> >
> > So, the DTSTART is not always the first instance in the recurrence set,
> > and an  EXRULE does not necessarily exclude the DTSTART. Consequently, a
> > recurrence  rule does not necessarily generate the DTSTART as its first
> > date/time.
>
> But again, 4.8.5.2 states: 'The "DTSTART" defines the first instance in the
> recurrence set.'. I consider that a stronger statement than 'can be used to
> exlcude...'. As defined it 'always excludes the DTSTART'. 

Well, first, there is that "if specified", which I understand as "if generated 
by the rule". And second, if DTSTART is excluded by EXRULE or EXDATE it is 
not the first instance in the recurrence set, so we have a contradiction in 
any case. 

> The bottom line is this just re-emphasizes why EXRULE is a real problem and
> should be deprecated.

The same problem goes with RRULE and the COUNT.

Cheers,
Reinhold

- -- 
- ------------------------------------------------------------------
Reinhold Kainhofer, Vienna University of Technology, Austria
email: reinhold at kainhofer.com, http://reinhold.kainhofer.com/
 * Financial and Actuarial Mathematics, TU Wien, http://www.fam.tuwien.ac.at/
 * K Desktop Environment, http://www.kde.org, KOrganizer maintainer
 * Chorvereinigung "Jung-Wien", http://www.jung-wien.at/
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.5 (GNU/Linux)

iD8DBQFFLRjYTqjEwhXvPN0RAmXLAKCV4iCotTPjZKIG+Didw3YsOsysjACfbnS+
Zvz0PYrq51CnHyZhvThw6Bc=
=fw2s
-----END PGP SIGNATURE-----