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Re: [Simple] Presence Relax NG schemas



Perhaps this is exactly the type of activity that should take place in the future SIMPLEt events. As I understand the issue, creating an über schema from the various PIDF + extension schemas isn't exactly straight forward (because of the UPA issue). So I would consider this as a helper in doing document validation for implementors.

As an aside, I use the xml2rfc tool as probably most of you do, and I use Relax NG schema (that I converted from Marshall's DTD) to validate my drafts. And it seems to work fine.

I think the Relax NG schema should simply be something that implementors can take, validate their presence documents and (after the dust settles) see what happened vs. the XML schema validation. If there are differencies, then that info is probably very valuable.

There is a bigger issue here: do we mandate that the presence documents are always validated using XML schema only, or is e.g. Relax NG also allowed?

Cheers,
Aki

ext Jonathan Rosenberg wrote:
I don't have any particular views on the pros/cons of XML schema vs. relax NG. However, my concern about this is whether there is value in having TWO definitions of the grammar for these documents. It seems that this is a recipe for interoperability problems. An XML-schema-using implementation might define a document that is valid according to the schema, but invalid according to the RELAX-NG definition. That would be a problem. If that never happens, and neither can the converse (a RELAX-NG compliant document that is not schema compliant), then the RELAX-NG description is isomorphic to the XML schema, and so what is the value exactly?

-Jonathan R.

Jari Urpalainen wrote:

Hi all!

I have submitted a draft <http://www.ietf.org/internet-drafts/draft-urpalainen-simple-presence-relaxng-00.txt>

(targeted as informational). This memo describes PIDF + extension
schemas written with the Relax NG schema language. These were
produced because with the W3C schemas it is not possible to write
reasonable combination presence schemas doing on-the-fly validation
(because of the paranoid UPA constraint specified in the appendix H
of W3C structures spec). So these are meant for publishers of
presence information and the rules given in these schemas are thus
stricter than the W3C schemas. Therefore, instance documents that
validate with these shall also validate with the W3C schemas. The set
incluces schemas for PIDF, datamodel, RPID, CIPID and CAPS. There are
still some minor differencies between these and PIDF extension
schemas (some "last minute" changes in I-D's). So these are not meant
to replace W3C schemas, they are just produced to decrease
interoperability problems with "real" implementations. W3C Schema 1.1
spec may eventually have a proper wildcard definition etc., but
before it happens these schemas can be utilized.

Any comments ? Jari





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