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

Re: anonymous abouts (blank node creation)

From: Ivan Herman <ivan@w3.org>
Date: Fri, 20 Jul 2007 14:23:24 +0200
Message-ID: <46A0A93C.2010208@w3.org>
To: Niklas Lindström <lindstream@gmail.com>
CC: RDFa <public-rdf-in-xhtml-tf@w3.org>


Niklas Lindström wrote:
> Hi Ivan,
> 
> I think I like this suggestion. Just to be clear, wouldn't it be
> necessary to write:
> 
>    <div about="[_:]">
> 

I am not sure. Somebody (?) is supposed to write down the RDFa rules for
these.

> though (and not just @about="_:")? That being the case, *perhaps*
> @about="[]" could be enough? Although it may not be symmetrical enough

Yes, if you are right with the one above, than [] could also work...

Let us wait for the exact write up of the RDFa rules for URI
abbreviation (/me avoid using the "C" word...)

Ivan

> 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
>>
>>

-- 

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 Friday, 20 July 2007 12:23:30 GMT

This archive was generated by hypermail 2.2.0+W3C-0.50 : Tuesday, 8 January 2008 14:15:08 GMT