[uf-discuss] all day events

Mark Mansour mark at lifelint.com
Thu Feb 16 03:45:50 PST 2006

> You're right there is a date type, but we ignore it for good reason.
> Sorry that I took me awhile to respond, but I couldn't remember at
> first the exact reason for the way we do it.

Hey, not a problem.

> Anyway, the reason we confound the DATE and DATETIME types is that
> they are treated essentially the same by calendaring applications.
> For example, I just created an event in Apple's iCal.app for 2/6-2/9
> (last week), then exported it:

> > VERSION:2.0
> > X-WR-CALNAME:blah
> > PRODID:-//Apple Computer\, Inc//iCal 2.0//EN
> > X-WR-RELCALID:4BA2A3D9-23D1-495E-BFA2-AA439939BF0C
> > X-WR-TIMEZONE:America/Los_Angeles
> > DTEND;VALUE=DATE:20060209
> > SUMMARY:blah
> > UID:26F9A96A-5D25-455A-8240-12EED1ADF63C
> > DTSTAMP:20060214T070829Z
> Notice that, though I created the event as ending on 2006-02-08, it
> put 2006-02-09, making 2006-02-09 == 2006-02-09T00:00.

I'm not really clear on the argument you are making here.  I see two
issues with your statement (a - that calendaring programs like the
Apple one do understand both dates and datetimes; and b - that you've
said the end date is both the 8th and the 9th in your example (and I
do understand the idea that end dates are exclusive)) - but this isn't
really what I was trying to convey.

Let me try to restate the issue again in a different way, maybe it
will clear things up.

I reckon:
- 2006-02-09 is a date
- 2006-02-09T00:00 is a 'floating' datetime
- semantically (sorry, I don't like that word) 2006-02-09 == 2006-02-09T00:00
- but 2006-02-09T00:00 is the ugly way of saying 2006-02-09
- the hcard-parsing page says "For properties which take an ISO8601
datetime value, parsers *should* pad any necessary precision (e.g.
seconds) and *should* normalize any datetimes with timezone offsets"
- since there is no timezone, none should be present in the final date
(or datetime)

therefore the proper way to write 2006-02-09 is 2006-02-09T00:00:00.

In my blog entry I was asserting that is was neater to write the
datetime simply as a date - that was a big portion of my blog entry -
perhaps not as clearly expressed as it should have been.  Again, I
just think 2006-02-09 is neater.

For the sake of all of those concerned (who have even bothered to read
this far) that we agree on, as you said earlier, that (drumroll
--->    2006-02-09 == 2006-02-09T00:00:00

Therefore it would be nice to add clarification to the hcard-parsing spec saying
- all dates information should be expressed as datetimes
- 'all day events' *may* be represented without a timezone, if they
are a floating time (as described in rfc2445), but *should* have the
hour, minute and second represented as 00:00:00



> -ryan
> --
> Ryan King
> ryan at technorati.com
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picking the lint off your life

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