LC-149. extending: Provide guidance on extending schema for schem as?

Dear Dr. Hunter and the MPEG-7 :

The W3C XML Schema Working Group has spent the last several months working
through the comments received from the public on the last-call draft of the
XML Schema specification. We thank you for the comments you made on our
specification during our last-call comment period, and want to make sure you
know that all comments received during the last-call comment period have
been recorded in our last-call issues list
(<http://www.w3.org/2000/05/12-xmlschema-lcissues>).

You raised two questions registered as issue LC-149:

* Recommended extensibility mechanisms (e.g. XSL/XSLT?) so MPEG-7 can add
additional attributes to the XML Schema specification and define their own
constructs to satisfy MPEG-7-specific requirements; 

This additional information could be added to the <appinfo> tag of
<annotation>.  Note that <appinfo> can contain any elements.

* The behaviour of an XML Schema valid parser in the case of an "unknown"
(MPEG-7) tag and attribute in the schema specification.

<appinfo> is defined in the schema for schema to have "lax" processing, so
XML Schema valid parsers are will validate the information if possible.  In
3.9:
"lax :
If the item, or any items among its [children] if it's an element
information item, has a uniquely determined declaration available, it must
be valid with respect to that definition, that is, validate where you can,
don't worry when you can't."

It would be helpful to us to know whether you are satisfied with this
explaination.

Regards,
Don Mullen
XML Schema Language Working Group

Received on Monday, 9 October 2000 18:17:40 UTC