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Re: anonymous abouts (blank node creation)

From: Ben Adida <ben@adida.net>
Date: Fri, 20 Jul 2007 07:36:30 -0700
Message-ID: <46A0C86E.8040103@adida.net>
To: Ivan Herman <ivan@w3.org>
CC: Niklas Lindström <lindstream@gmail.com>, RDFa <public-rdf-in-xhtml-tf@w3.org>


Ivan, Niklas,

I'll start replying to the new thread, but I want to point out my strong
preference for not forcing authors to use the [] notation for common use
cases. I don't think we need to, either.

-Ben

Ivan Herman wrote:
> 
> 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
>>>
>>>
> 
Received on Friday, 20 July 2007 14:39:48 GMT

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