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Re: anonymous abouts (blank node creation)

From: Ivan Herman <ivan@w3.org>
Date: Fri, 20 Jul 2007 16:57:02 +0200
Message-ID: <46A0CD3E.8050908@w3.org>
To: Ben Adida <ben@adida.net>
CC: Niklas Lindström <lindstream@gmail.com>, RDFa <public-rdf-in-xhtml-tf@w3.org>
Hi Ben,

If you can convince me, I am the first one to be very happy about it!:-)

Ivan

Ben Adida wrote:
> 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
>>>>
>>>>
> 

-- 

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 14:57:27 GMT

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