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Addition of duration to partially-specified dateTimes

From: James Clark <jjc@jclark.com>
Date: Wed, 24 Apr 2002 12:53:19 +0700
Message-ID: <009301c1eb54$568c4ca0$3500a8c0@bkk.thaiopensource.com>
To: "XML Schema Comments" <www-xml-schema-comments@w3.org>
Section E.1 contains the sentence:

"If a field in S is not specified, it is treated in the calculation as if it
were the minimum allowed value in that field, however, after the calculation
is concluded, the corresponding field in E is removed (set to unspecified)."

I think this sentence is in error and should be deleted.

The ordering relation for eg gYear specifies: "the order relation on gYear
values is the order relation on their starting instants".  In this case as
in others, we only need to compare fully-specified dateTime instants.

The value space of gYear must be considered as containing both the year
number and the time zone (if any).  To compare two values in the gYear value
space, you convert them to values in the dateTime value space (by using
their starting instants).  Then you compare those two dateTime values using
the algorithm in 3.2.7.3.

That sentence in section E.1 only makes sense if you take the view that the
value space of the partially specified dateTimes (like gYear, gMonth) does
*not* include time zones; in this case, you would need to normalize out the
time-zone before converting to a time-instant for comparison, and so would
be applying addition to a partially-specified date time.  But this leads to
nonsense results, as Kawaguchi-san pointed out:

http://lists.w3.org/Archives/Public/www-xml-schema-comments/2001JanMar/0365.
html

James
Received on Wednesday, 24 April 2002 02:10:21 GMT

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