Re: Associating schema with document

[Murata Makoto <mura034@attglobal.net>]

> Thus I believe the compatibility spec should provide a way for an instance
> to indicate what RELAX NG schema should be used for compatibility
> processing.  The obvious mechanism for this would be a processing
> instruction in the prolog.

Somebody has repeatedly said to me that we should provide a mechanism for 
documents to reference to RELAX NG schemas.  Although I have some sympathy, 
I am not sure if such a mechanism is a good idea.

First, is such a mechanism merely a hint (as in XML Schema)?   If so, we have 
an interoperability problem.  Or, is it definitive?  Then, the recipient will 
be forced to use the schema of the sender.

Second, what about RDDL?  Do we ignore it?

Third, how does such a mechanism interact with XML Catalogs?  It can 
map a URI reference to another URI reference.

Fourth, given an XHTML document containing RDF metadata, I would like to write 
a framework in RELAX Namespace and associate this framework with the document.  
Such a framework will then reference to a RELAX NG schema and also reference 
to a RDF Schema schema.  In this case, I do not want to reference to a 
RELAX NG grammar directly from a document.

Fifth, does each schema language provide its own mechanism for referencing 
to a schema?  Should we care schema language negotiation?

I am not opposing to the idea.  But I think that we have to have 
an overall picture and then make a decision.


Cheers,

Makoto