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Re: [Bug 3027] erroneous date example

From: C. M. Sperberg-McQueen <cmsmcq@blackmesatech.com>
Date: Mon, 2 Nov 2009 13:53:33 -0700
Cc: "C. M. Sperberg-McQueen" <cmsmcq@blackmesatech.com>
Message-Id: <99ECACFF-D9A6-4443-A3C9-9477F121E7EC@blackmesatech.com>
To: www-xml-schema-comments@w3.org, Kevin Braun <kbraun@obj-sys.com>

On 2 Nov 2009, at 13:30 , bugzilla@wiggum.w3.org wrote:

> http://www.w3.org/Bugs/Public/show_bug.cgi?id=3027
> --- Comment #13 from Kevin Braun <kbraun@obj-sys.com>  2009-11-02  
> 20:30:37 ---
> Regarding the part that reads "others, such as '23:00:00-03:00' and
> '02:00:00Z', now denote unequal values": it is not clear to me that  
> these would
> have been considered equal under 1.0.  I say this because XML Schema  
> 1.0, Part
> 2, section 3.2.8 "time" says "The order relation on time values is  
> the Order
> relation on dateTime ( using an arbitrary date."  This,  
> with the above
> statement, seems to imply that under 1.0 (adding an arbitrary date),
> '2009-11-02T23:00:00-03:00' denoted a value equal to  
> '2009-11-02T02:00:00Z',
> which I don't think was the case.

1.0 operationalized the time comparison by (a) normalizing to
UTC, (b) supplying an arbitrary date (e.g. 31 December 1971), and
(c) comparing the resulting times.

1.1 changes that, in response to what has been called the Japanese
shop hour or Tokyo-Chicago telcon problem, by reversing the order
of steps (a) and (b).  If you supply the date first, and then
normalize to UTC, the result is, as you suggest, different.

I will seek out chapter and verse if necessary, but I don't have
time to do that at the moment.  My confidence that 1.0 behaved
as described is due in part to clear memories of the WG meetings
in which we discussed the discrepancies between XSD's treatment of
date and time related types and their treatment in XPath 2.0 and
related specs, and of the discussions of the Japanese store-hour
and Tokyo-Chicago telcon issues.

* C. M. Sperberg-McQueen, Black Mesa Technologies LLC
* http://www.blackmesatech.com
* http://cmsmcq.com/mib
* http://balisage.net
Received on Monday, 2 November 2009 20:54:04 UTC

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