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Re: anonymous abouts (blank node creation)

From: Niklas Lindström <lindstream@gmail.com>
Date: Fri, 20 Jul 2007 14:13:05 +0200
Message-ID: <cf8107640707200513m5075c8a1l7062cc79f2873633@mail.gmail.com>
To: "Ivan Herman" <ivan@w3.org>
Cc: RDFa <public-rdf-in-xhtml-tf@w3.org>

Hi Ivan,

I think I like this suggestion. Just to be clear, wouldn't it be
necessary to write:

    <div about="[_:]">

though (and not just @about="_:")? That being the case, *perhaps*
@about="[]" could be enough? Although it may not be symmetrical enough
or even look broken.. Sure it looks exactly the way blank nodes are
expressed in Notation 3. But that may be unfortunate of course, since
it would suggest that you could use N3 in the attribute value (which
naturally isn't the case at all). That said, it does look succinct and
"clean" in my eyes.. Though "_:" (within square brackets in "plain
URI" attributes like @about) may be more consequential I guess.

Best regards,
Niklas



On 7/18/07, Ivan Herman <ivan@w3.org> wrote:
> Some of the issues in the past days made me thing a bit. I refer here to
>  issues like
>
> http://lists.w3.org/Archives/Public/public-rdf-in-xhtml-tf/2007Jul/0143.html
> http://lists.w3.org/Archives/Public/public-rdf-in-xhtml-tf/2007Jul/0136.html
> http://lists.w3.org/Archives/Public/public-rdf-in-xhtml-tf/2007Jul/0137.html
> http://lists.w3.org/Archives/Public/public-rdf-in-xhtml-tf/2007Jul/0142.html
>
> One of the problems we are fighting with is when to generate a new blank
> node and how...
>
> I guess we will have something special for about values along the lines
> of turtle for blank nodes, right? about="_:blabla" means a blank node
> with nodeId (to use the RDF/XML terminology) "blabla". But what is the
> meaning of about="_:". Well, mentally, I could say that this means a
> blank node hose nodeId I do not care about, just let the system choose
> whatever this wants.
>
> What this means is that if I say
>
> <div property="a:b" about="_:">blabla</div>
>
> that would yield
>
> [ a:b "blabla" ]
>
> Or, if there are more things in <div> the blank node would act as a
> common subject, because the same rules for @about would apply.
>
> In
>
> http://lists.w3.org/Archives/Public/public-rdf-in-xhtml-tf/2007Jul/0137.html
>
> Mark proposed that
>
> <div instanceof="foaf:Person">
>     ...
> </div>
>
> would automatically create a blank node and instanceof would apply to
> that. In fact, we could say that the real code here is:
>
>
> <div instanceof="foaf:Person" about="_:">
>     ...
> </div>
>
> in which case the rule from Mark simply come from our usual rules,
> without any exception to instanceof (compared to the usage of @rel, ie,
> to what the attribute applies to).
>
> The other issue was to create a list of anonymous blank nodes. Well
>
> <ul instanceof="rdf:List">
> <li about="_:" instanceof="foaf:Person" property="foaf:name">A</li>
> <li about="_:" instanceof="foaf:Person" property="foaf:name">B</li>
> </ul>
>
> would exactly do it. Note that if of the authors have his/her own
> resource, than
>
> <ul instanceof="rdf:List">
> <li about="_:" instanceof="foaf:Person" property="foaf:name">A</li>
> <li about="http://www.a.b.c" instanceof="foaf:Person"
> property="foaf:name">B</li>
> </ul>
>
> would of course do it, and keep it very symmetrical.
>
> We already have a rule on the creation of 'empty' nodes, ie
>
> <div rel="a:b">....</div>
>
> means setting a new blank node. We could keep that rule, too, I do not
> think it would lead to any harm...
>
> This is really just an uncooked idea, may be absolute rubbish. But maybe
> it is worth looking at it...
>
> Ivan
>
>
>
>
>
>
>
> --
>
> Ivan Herman, W3C Semantic Web Activity Lead
> URL: http://www.w3.org/People/Ivan/
> PGP Key: http://www.cwi.nl/%7Eivan/AboutMe/pgpkey.html
> FOAF: http://www.ivan-herman.net/foaf.rdf
>
>
Received on Friday, 20 July 2007 12:13:10 GMT

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