W3C home > Mailing lists > Public > public-rdf-in-xhtml-tf@w3.org > July 2007

Re: Determination of subjects/objects

From: Ben Adida <ben@adida.net>
Date: Fri, 20 Jul 2007 08:08:30 -0700
Message-ID: <46A0CFEE.1060607@adida.net>
To: Ivan Herman <ivan@w3.org>
CC: W3C RDFa task force <public-rdf-in-xhtml-tf@w3.org>


> Niklas has already touched upon the problem of @id, and I was also a bit
> surprised to see it in the list.

The treatment of @id has not changed recently :) As you suggest, by
itself it doesn't do anything: you need @rel or @instanceof to have it
do something. Consider the following driving use case:

<div id="me" instanceof="foaf:Person">

Now if you have just:

<div id="me">

then that doesn't trigger anything, not even a subject for the contained
elements, as that is just HTML without RDFa.

So when you say:

> However... I presume it is true that a change in the current 'RDF
> identity' as an effect of an @id happens _only if there is an RDFa
> related attribute on that element_, ie, if there is an @rel, @property,
> etc, around. Other than that, the current RDF identity remains intact
> while going down the XML tree. Is that so? If yes, than an @id appearing
> on one of the elements in the tree may not have any effect. Is that
> correct? With that additional rule, the usage of @id may not be that
> dangerous after all.

you're exactly right.

> Having said that, I wonder whether it is not simpler to remove @id from
> that algorithm altogether. It may be a little bit more convoluted for
> the user but certainly safer.

I think some use cases become very clunky, then. Let's say you want to
say you created the page. I'd like to write:

<div id="me" rel="dc:creator">

You'd have to write

<div id="me" rel="dc:creator" href="#me">

Is that really necessary?

I think the rule of @id being used when RDFa is invoked makes sense. On
its own, it doesn't trigger anything.

Received on Friday, 20 July 2007 15:11:42 UTC

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