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[XQuery] implicit timezone

From: Xavier Franc <xfranc@online.fr>
Date: Tue, 25 May 2004 19:39:44 +0200
Message-ID: <40B384E0.9010701@online.fr>
To: public-qt-comments@w3.org

There is a little oddness about the implicit timezone: it seems to 
depend only
on the dynamic context:

 >        2.1.2 Dynamic Context
 > [Definition: Implicit timezone. This is the timezone to be used when 
a date, time, or dateTime value that does not
 > have a timezone is used in a comparison or in any other operation. 
This value is an instance of
 > xdt:dayTimeDuration that is implementation-defined.]

Typically, this implementation-defined timezone will be the local timezone,
which in many countries is not the same in winter and in summer,
due to Daylight Saving Time.

So the expression xs:date("2004-01-01") wont
correspond with the same UTC time if it is computed in
winter or summer.

However, it is a bit odd to apply a summer timezone (DST)
to a winter date ... It seems that it should depend
on the date itself, shouldn't it ?

And actually, this is what happens for example
with Java classes: if you parse "2004-01-01" with the appropriate
java.text.DateFormat, you dont get the same
difference to GMT as you get when parsing "2004-06-01".

This can be a practical issue in XQuery applications.

By the way, if somebody can explain me what is the meaning
of a timezone applied to a DATE, s/he is welcome.
I understand of course the meaning of a timezone
applied to a dateTime, but would anybody say
"Christmas 2004 CST, not to be confused with
 Christmas 2004 GMT " ?
Received on Tuesday, 25 May 2004 13:40:54 UTC

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