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Re: Issue on the latest syntax document: placement of @instanceof

From: Ivan Herman <ivan@w3.org>
Date: Tue, 11 Sep 2007 14:32:32 +0200
Message-ID: <46E68AE0.3040907@w3.org>
To: "public-rdf-in-xhtml-tf.w3.org" <public-rdf-in-xhtml-tf@w3.org>, Ben Adida <ben@adida.net>
Ben et al,

I just see that what I write below is _not_ in line what is currently in
the primer. Indeed, the example in the primer is:

...<p instanceof="cal:Vevent"

which is interpreted in RDF as

       rdf:type cal:Vevent;

indeed, my interpretation below would then yield

<#> rdf:type cal:Vevent;

What this means is that the syntax document and the primer are in line
(and my implementation is wrong:-). Is this the final decision of the group?

Also, more on the descriptive side, if one has an @about and wants to
give a type to it, then something more convoluted is necessary:

<span about="#a"><span instanceof="a:b"/></span>

(Is this valid? Ie, can the <span> element be empty?)


Ivan Herman wrote:
> My apologies if that was discussed on the telco. I saw in [1] that this
> issue came up; maybe I am banging on open doors. If so, sorry about that...
> The question: what is the subject for rdf:type in a construction like:
> <span about="#a" instanceof="a:b">...
> Following the Processing steps of
> http://www.w3.org/MarkUp/2007/ED-rdfa-syntax-20070906/
> I believe the answer is:
> [] rdf:type a:b.
> ie, the subject is a new bnode.
> Why:
>  - in step 2, item 1 of the processing steps [current object resource]
> is set to a new bnode (there is no @href, @resource, etc to set it
> otherwise)
>  - in step 3, item 2 of the processing steps triples are generated using
> the [current object resource] as subject for rdf:type
> I do not think this is what we want. I think what we want is
> <#a> rdf:type a:b.
> Informally, I think what we want to say is that the subject of the type
> should be [current resource] in case no triples are generated with the
> [current object resource], and the latter otherwise...
> Taking into account the problem with chaining, and my proposed changes
> in [2], this is what I propose for the Processing step
> - Remove step 2 from processing step 3
> - Insert a new step between processing step 4 and 5 to set the type
> values. This is essentially the same text as what was removed from the
> previous setp, but the type value should be set on [current resource]
> (an not on [current object resource] as it currently says). Also, the
> last remark (referring to [chaining]) should be removed.
> I believe that takes care of the problems.
> Ivan
> [1] http://www.w3.org/2007/09/06-rdfa-minutes.html
> [2]
> http://lists.w3.org/Archives/Public/public-rdf-in-xhtml-tf/2007Sep/0058.html


Ivan Herman, W3C Semantic Web Activity Lead
Home: http://www.w3.org/People/Ivan/
PGP Key: http://www.ivan-herman.net/pgpkey.html
FOAF: http://www.ivan-herman.net/foaf.rdf

Received on Tuesday, 11 September 2007 12:32:30 UTC

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