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Re: Determination of subjects/objects (was: ISSUE-42)

From: Ben Adida <ben@adida.net>
Date: Fri, 27 Jul 2007 08:36:03 -0700
Message-ID: <46AA10E3.9020801@adida.net>
To: public-rdf-in-xhtml-tf@w3.org


Ivan,

I finally got a chance to look this over. There are some things I
disagree with in the examples, and I believe they highlight an issue
with the rules I laid out :) I'm highlighting only the ones I disagree with.

> <ul instanceof="rdf:Seq">
> <li about="#A">blabla <span property="p:q">bla2</span></li>
> <li href="#B">blabla <span property="p:q">bla3</span></li>
> </ul>
> 
> yields
> 
> <ul instanceof="rdf:Seq">
> <li rel="rdf:_1" about="#A">blabla <span property="p:q">bla2</span></li>
> <li rel="rdf:_2" href="#B">blabla <span property="p:q">bla3</span></li>
> </ul>
> 
> yields
> 
> [ a rdf:Seq;
> 	rdf:_1 <#A>;
> 	rdf:_2 <#B>.
> ]
> <#A> p:q "bla2".
> <#B> p:q "bla2".
> 
> Note that, as a side effect of the Ben rules, there is _no_ difference
> between @about and @href in this setting...

Okay, *this* is a problem, I think. I know the way I worded "the rules",
it appears that @about is then the RDF identity, so it appears that it
can be the object when you write:

   <li rel="rdf:_1" about="#A">

but I think that is very wrong. Because, if you add @resource, then
@about suddenly becomes the subject. And that's quite confusing.

It leads me to wonder if the rules are a bit wrong or inconsistent.

If you were to write resource="#A", then I would agree, but as it
stands, it bothers me. And, in fact, this is the Achille's heel of this
 "syntactic sugar for collections" issue: if you add other RDFa
attributes, you screw up the resulting output.

> If I also use the proposed @about="_:" notation then
> 
> <ul instanceof="rdf:Seq">
> <li about="_:">blabla</li>
> <li about="_:">blabla</li>
> </ul>
> 
> yields
> 
> <ul instanceof="rdf:Seq">
> <li rel="rdf:_1" about="_:">blabla <span property="p:q">bla2</span></li>
> <li rel="rdf:_1" about="_:">blabla <span property="p:q">bla2</span></li>
> </ul>
> 
> which leads to
> 
> [ a rdf:Seq;
>   rdf:_1 [ p:q "bla2". ];
>   rdf:_2 [ p:q "bla2". ].
> ].
> 
> I have the impression that things begin to fall into their place nicely

I have a visceral problem with about="_:", and that is that it makes
bnodes explicit, which I really don't want to do to HTML authors. That's
just too much RDF.

We may begin to hit diminishing ROI here, and I'm starting to lean
towards supporting fewer of these constructs in order to not complicate
the syntax. I can't see myself being convinced that about="_:" is going
to help without hurting more....

-Ben
Received on Friday, 27 July 2007 15:36:11 GMT

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