Subject: Re: Semantics of date vs. date/time EXDATEs

From: [email-masked]
Date: Wed, 28 Feb 2001 15:01:06 -0500

Federico asked:
>If I add EXDATE properties, what
>is the difference between making them date or date/time values? 

Well, an EXDATE with a date-time value would only filter out the instance 
that occurs / begins at that date and time.  An EXDATE of date-only would 
filter out all instances that occur / begin at that date (the times are 
implied to be all day or any time that day).

>Does a date/time value only affect occurrences whose start time is
>precisely that date/time?  And does a date value affect all
>occurrences that happen during that day, or just the ones whose start
>time is midnight?

The original intent of the filter abilities was to match start times, not 
'in progress' times.  For example, a movie theatre shows a 2 hour long 
movie every 1.5 hours (on 2 screens).  If one screen was unavailable for 
use for whatever reason they could use a EXDATE;VALUE=DATE-TIME to block 
out the entry that would have begun at a particular time.  They do not 
want to block out the other screen that is already showing the movie. 

Also, it is a lot simpler and more realistic to filter entries as you 
guessed rather than filtering based on overlapping times.

Bruce
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Bruce Kahn                                INet: [email-masked]
Iris Associates                          Phone: 978.392.5335
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