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Re: Display values for RDFa object URLs

From: Niklas Lindström <lindstream@gmail.com>
Date: Wed, 8 Aug 2007 11:24:59 +0200
Message-ID: <cf8107640708080224oa5aa64n2f7ea8125c2d46ba@mail.gmail.com>
To: "Manu Sporny" <msporny@digitalbazaar.com>
Cc: "RDFa mailing list" <public-rdf-in-xhtml-tf@w3.org>

Hello!

> something like this:
>
> <div instanceof="hmedia:Audio" about="#song">
>    <a href="http://www.bitmunk.com/sample/6011101"
>       rel="hmedia:sample" about="#HREF" property="dc:title">
>       A Sample
>    </a>
> </div>
>
> or in other words, we'd like the following (N3):
>
> <#song> rdf:type hmedia:Audio;
>         hmedia:sample <http://www.bitmunk.com/sample/6011101> .
> <http://www.bitmunk.com/sample/6011101> dc:title "A Sample" .

Absolutely, you can get that (verified with Ivan's pyRdfa) from this:

   <div about="#song" instanceof="hmedia:Audio">
       <a rel="hmedia:sample"
          href="http://www.bitmunk.com/sample/6011101">
           <span property="dc:title">A Sample</span>
       </a>
   </div>


> Niklas, apologies, as it seems that I didn't state the problem very well
> the first time around :) - we'd like something a bit more terse than
> what you proposed (even though it did solve the problem I had previously
> stated).
>
> Apologies if this makes no sense, as I'm still coming up to speed with
> what is/isn't possible via chaining in RDFa. Can we get the above N3
> without having to use a hmedia:Sample class?

NP, I mostly focused on syntactic stuff, not the terseness. As seen in
the last example, it's a little more succinct. The extra span doesn't
cost much IMHO.

First, just a note. You don't need @instanceof really (which is not
final yet AFAIK), it is mostly just syntactic sugar for an rdf:type
statement. It comes in handy in some places as it also affects
chaining (mainly when you want a bnode), but can in general be
replaced by a more explicit regular @rel="rdf:type" + resource
reference (in a nested element - if used in the same, chaining makes
the *type* the chained subject). Also, @class has been voted off - it
will not (for now) mean anything in the RDFa sense (which is a good
thing in my opinion).


Now, the example you give is something that crossed my mind earlier
when Ivan mentioned that @property isn't affected by the chaining if
on the same element (see
<http://lists.w3.org/Archives/Public/public-rdf-in-xhtml-tf/2007Jul/0212.html>,
and Ben's reply). This was as it has been, so it was just an
observation. However, your example here illustrates that it *may* be
more intuitive if the rules where changed so that @property has the
"corresponding RDF identity" as its subject. I am not at all sure
about that though, it definitely could invalidate a lot of other
examples/uses. So I recommend the use of a nested span with @property
to be certain of getting it right (as right as can be pending
recommendation that is).

Do any others have thoughts about this?


Best regards,
Niklas
Received on Wednesday, 8 August 2007 09:25:08 GMT

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