Subject: RE: Duration: Does 1 day == 24 hours?

From: [email-masked]
Date: Wed, 28 Mar 2001 11:48:48 -0600

> There is the further concept of "for just this one date" or 
> "all-day" which
> I do NOT think should be set in the standard, but should be 
> left to the
> implementation to convert to the appropriate durations and 
> start times (i.e.
> DTSTART of just after midnight, DTEND of just before midnight for some
> "all-day", or "DTSTART set by user and DTEND of just before 
> midnight of that
> date for "just this day" type of events." 

Shannon:

The ability to specify an all day event is already in RFC2445. For example:

DTSTART;VALUE=DATE:20010328
DTEND;VALUE=DATE:20010328

or (as we have been discussing)

DTSTART;VALUE=DATE:20010328
DURATION:P1D

>Since this is a 
> user interface
> issue - easily expressed under the current standards, I think 
> it would be
> poor use of duration: day to use it to mean one of the above 
> meanings -
> these should be converted and implemented by the application.
> 

I disagree. As evidence, how would you interpret a DURATION:P1M? Is it 30
day*24 hours? Or is it 28, 29 or 31? And what do you do for the other
calendar specific forms of DURATION values? 

The time specific values provide clock based granularity. The calendar
specific value provide date based granularity. To take the latter and turn
it into the former defeats the benefits of this type of DURATION.

Now, as for interoperability, I would guess that this form is a "nice to
have", but not a "must have" in most requirements documents. As such, it
would be a candidate for an optional component in my Static Conformance
Requirements document ;-)

-- Frank

---

From: Alan Davies <[email-masked]>
Date: Wed, 28 Mar 2001 13:13:41 -0500

>DTSTART;VALUE=DATE:20010328

What we were discussing was a date and time
with a duration expressed in days:

DTSTART;VALUE=DATE:20010328T235000
DURATION:P1D

Although now that dates alone are being discussed,
how would you interpret this- would it be considered
invalid?:

DURATION:PT11H

--Alan

---

From: Alan Davies <[email-masked]>
Date: Wed, 28 Mar 2001 13:04:25 -0500

>DTSTART;VALUE=DATE:20010328

Yes the duration of this event is one whole day (24/25
hours, but that's another issue).

>calendar specific forms of DURATION values?

Nothing above a week is mentioned in RFC2445 4.3.6.

>it into the former defeats the benefits of this type of DURATION.

but RFC2445 gives a duration example that combines both: P15DT5H0M20S

How should this be interpreted- does a day have a different
meaning when used with and without a time?

--Alan

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From: John Stracke <[email-masked]>
Date: Wed, 28 Mar 2001 13:16:57 -0500

[email-masked] wrote:

> I disagree. As evidence, how would you interpret a DURATION:P1M?

As a violation of the spec.

--
/================================================================\
|John Stracke    | http://www.ecal.com |My opinions are my own.  |
|Chief Scientist |===============================================|
|eCal Corp.      |All I ask is a chance to prove that money can't|
[email-masked]|make me happy.                                 |
\================================================================/

---

From: John Stracke <[email-masked]>
Date: Wed, 28 Mar 2001 13:19:09 -0500

> I disagree. As evidence, how would you interpret a DURATION:P1M?

I just misspoke.  P1M means "one minute".

--
/==============================================================\
|John Stracke    | http://www.ecal.com |My opinions are my own.|
|Chief Scientist |=============================================|
|eCal Corp.      |"There will be no more there. We will all be |
[email-masked]|here."--networkMCI ad                        |
\==============================================================/

---

From: Eric Busboom <[email-masked]>
Date: Wed, 28 Mar 2001 12:11:04 -0800 (PST)

> DTSTART;VALUE=DATE:20010328

Gack. I don't think we cover this one. I will add it as an issue. 

eric.