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Resource type issue (Re: Suggestions for rdf:List and a value type shorthand)

From: Ivan Herman <ivan@w3.org>
Date: Tue, 23 Aug 2011 11:52:20 +0200
Cc: public-rdfa-wg <public-rdfa-wg@w3.org>
Message-Id: <B5EEEA83-9744-40B7-8671-ACA1953815AB@w3.org>
To: Niklas Lindström <lindstream@gmail.com>


I'd prefer to put this in a separate thread because it is a different problem in my view...

> ## The missing object type feature
> With the above, we have touched upon what some consider a missing
> feature: the ability to have an rdf:type shorthand for the object.
> This takes care of a need some (including myself) have had with
> unobtrusively typing a resource in the same element as @rel.
> Example:
>    <div rel="dc:hasPart" resource="#ch-1" resourcetype="bibo:Chapter">
>      <h2 property="dc:title" lang="en">One</h2>
> Yielding:
>    <> dc:hasPart <#ch-1> .
>    <#ch-1> a bibo:Chapter;
>        dc:title "One"@en .
> Granted, adding "yet another" attribute might be considered to add
> even more complexity. Personally I feel that it would clear some
> things up though. And it would provide us with means for *both*
> rdf:List creation (by special treatment of rdf:List) *and* unobtrusive
> typing of the object.

I can see the value of this indeed. But there are some questions... Eg, what happens if somebody writes:

<span rel="dc:hasPart" resourcetype="bibo:Book">....<

I guess resourcetype would be quietly forgotten, right, because there is no explicit @resource/@href?

Alternatively, I think we may want to look at the semantics of typeof in general. Indeed, if I look at the example using typeof, one, in my view natural, way of encoding that would be something like

<div rel="dc:hasPart" resource="#ch-1">
  <h2 property="dc:title" lang="en" typeof="bibo:Chapter">One</h2>

but it won't work: according to our rules this will generate

<simple.xhtml> dcterm:hasPart ns1:ch-1 .
[] a bibo:Chapter;
    dcterm:title "One"@en .

due to the rule that unexpectedly creates a blank node out of the blue. In my view typeof should be a semantical shorthand for 

<... relt="rdf:type" resourcet="CLASSURI>

applying exactly the same rules as for relt as for rel (and resourcet would give the type), without generating any hanging rels.

That being said, all this may be too late. I am a bit wary opening such issues again; at some point we have to stop things and freeze RDFa 1.1. I do not want to drag on, in spite of the issues...


Ivan Herman, W3C Semantic Web Activity Lead
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Received on Tuesday, 23 August 2011 09:49:53 UTC

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