RE: MS-FO-LC1-009: TZ preservation considered problematic

Michael:

Thank you for your comment.  The WGs discussed this at the joint meeting
in Toronto on 9/15/2003 and decided not to

accept your recommendation.

 

As you know, we have gone a long way with this.  The XML Schema WG, on
our urging, has decided to introduce timezones into value space of data
and time types.  Final wording is in preparation for Schema 1.1.

 

If you are not happy with this resolution, please file a comment during
the next Last Call of the F&O or file a comment on the language
documents.

 

All the best, Ashok 

________________________________

From: public-qt-comments-request@w3.org
[mailto:public-qt-comments-request@w3.org] On Behalf Of Michael Rys
Sent: Monday, June 09, 2003 6:06 PM
To: public-qt-comments@w3.org
Subject: MS-FO-LC1-009: TZ preservation considered problematic

 

Class: Technical

 

In section 1.4 xs:dateTime, xs:date and xs:time values, the
specification requires to preserve timezones (presence or absence and
actual value).

 

This requirement makes the 3 atomic types into 3 tuple-types that have
some severe implementation consequences (for example, the full, physical
representation of the types are not binary comparable anymore).

 

It also contradict most date/time types available in other languages
where the following design has been the accepted way of dealing with TZ
and local values:

 

1.	Define a local and UTC-based datatype.
2.	Normalize the UTC-based datatype to Z-time.
3.	Provide formatting options to transform the UTC-based type to a
specific timezone.
4.	Provide transforms to move a local type instance to UTC-based
and vice-versa.

 

This design would be done in a similar way to the refactoring of the
xs:duration datatype.

 

Note: This request was already submitted by Xan Gregg in [1]

 

[1]
http://lists.w3.org/Archives/Public/public-qt-comments/2003May/0257.html