Re: [office-metadata] RDF/XML and XPath

[Bruce D'Arcus <bruce.darcus@OpenDocument.us>]

On Feb 9, 2007, at 3:47 PM, Michael Brauer wrote:

>> If that's the case, I don't see how it's our concern? I don't really 
>> see what we would put in the ODF spec that would pertain to this, 
>> except constraints on the syntax.
>
> The use case is that you have for instance a vCard instance in your 
> document, and you want to display some of its RDF objects (name, 
> street, etc.) in you letter.

OK, this is a good use case.

But it seems to me this does not change anything I said previously. 
Using XPath still won't work with an in memory model, and I still don't 
think it makes much sense to require two different mechanisms to 
display metadata in the content.

More importantly, perhaps the problem here is a quite specific one that 
is in fact not about RDF/XML syntax per se, but rather specific 
modeling. The issue, it seems to me, is blank nodes.

Let me explain:

The only reason you are looking to use XPath for the binding is to be 
able to access anonymous nodes in content. If all resources have URIs, 
there's no problem to do this simply with the metadata field approach 
in ways well-suited to both XML and RDF tools, and without having to 
use XPath.

So maybe the solution is to not allow blank nodes for those (rare, I 
suspect) encodings that must be able to be displayed in this very 
fine-grained way inline?

So if you want a user to be able to access vCard triples in a 
fine-grained way in content like this, then you end up with:

<rdf:Description rdf:about="http://ex.net/1";>
   <vcard:fn>Jane Doe</vcard:fn>
   <vcard:n rdf:resource="http://ex.net/2"/>
</rdf:Description>

<rdf:Description rdf:about="http://ex.net/2";>
   <vcard:given-name>Jane</vcard:given-name>
   <vcard:family-name>Doe</vcard:family-name>
</rdf:Description>

You can now access the family name directly in content without using 
XPath.

Problem solved, yes?

Bruce