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