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Re: Determination of subjects/objects

From: Ivan Herman <ivan@w3.org>
Date: Fri, 27 Jul 2007 18:27:06 +0200
Message-ID: <46AA1CDA.5080201@w3.org>
To: Mark Birbeck <mark.birbeck@formsPlayer.com>
CC: Ben Adida <ben@adida.net>, public-rdf-in-xhtml-tf@w3.org
Any term is fine with me at that point...

Ivan

Mark Birbeck wrote:
> Ivan,
> 
> I'm not sure that the 'RDF identity' is a useful term. I can see why
> Ben introduced it, to help formulate the rules summary, but I'm not
> sure it does actually help.
> 
> Another way to look at what is being done is that the 'context' for
> contained statements is being set; we could say that the context is
> set by the value of @href, or @resource, or some bnode, or whatever.
> 
> Regards,
> 
> Mark
> 
> On 27/07/07, Ivan Herman <ivan@w3.org> wrote:
>>
>> Ben Adida wrote:
>>>> [ a rdf:Seq;
>>>>      rdf:_1 <#A>;
>>>>      rdf:_2 <#B>.
>>>> ]
>>>> <#A> p:q "bla2".
>>>> <#B> p:q "bla2".
>>>>
>>>> Note that, as a side effect of the Ben rules, there is _no_ difference
>>>> between @about and @href in this setting...
>>> Okay, *this* is a problem, I think. I know the way I worded "the rules",
>>> it appears that @about is then the RDF identity, so it appears that it
>>> can be the object when you write:
>>>
>>>    <li rel="rdf:_1" about="#A">
>>>
>>> but I think that is very wrong. Because, if you add @resource, then
>>> @about suddenly becomes the subject. And that's quite confusing.
>>>
>>> It leads me to wonder if the rules are a bit wrong or inconsistent.
>>>
>>> If you were to write resource="#A", then I would agree, but as it
>>> stands, it bothers me. And, in fact, this is the Achille's heel of this
>>>  "syntactic sugar for collections" issue: if you add other RDFa
>>> attributes, you screw up the resulting output.
>>>
>> Ben, I remember I was surprised when realizing that, too. But, just to
>> really separate the issues, I do not believe this has anything to do
>> with the collection issue. The very same happens with
>>
>> <span rel="a:b" about="#b">asasfas</span>
>>
>> You rules in
>>
>> http://www.w3.org/mid/46A8D3ED.2080404@adida.net
>>
>> say:
>>
>> - - @rel (conversely @rev) creates triples with the given predicate. The
>> object of @rel (conversely the subject of @rev) is the "RDF identity" of
>> the current element...
>>
>> - the RDF identity of an HTML element is, in order of precedence
>>         - @resource
>>         - @href
>>         - @src if it's an IMG
>>         - @about
>>         - a new bnode
>>
>> meaning that we would get
>>
>> <> a:b #b.
>>
>> for the element above and if we added a @href then suddenly the @about
>> becomes the subject of a:b.
>>
>> I am not saying this is not confusing, I am just saying that this is
>> _not_ related to the collection syntactic sugar. Ie, I still believe the
>> collection issue is, essentially, closed (I can use @resource in all my
>> examples, eg, as resource="_:", without problems).
>>
>> I am not sure what to do with that stuff. I have to run now, maybe you
>> may want to look at the different cases with the @about removed from the
>> RDFI calculation.
>>
>>
>>
>> [snip]
>>> I have a visceral problem with about="_:", and that is that it makes
>>> bnodes explicit, which I really don't want to do to HTML authors. That's
>>> just too much RDF.
>>>
>>> We may begin to hit diminishing ROI here, and I'm starting to lean
>>> towards supporting fewer of these constructs in order to not complicate
>>> the syntax. I can't see myself being convinced that about="_:" is going
>>> to help without hurting more....
>>>
>> I do believe that (1) "_:" will be very rarely used and for RDF people
>> only but (2) in some edge cases it is difficult to avoid it. Any other
>> syntactic solution would lead to real complications I believe, and I
>> also believe that getting a sequence of anonymous and untyped bnodes is
>> sometimes necessary...
>>
>> Ivan
>>
>>
>>
>>> -Ben
>>>
>> --
>>
>> 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
>>
>>
> 
> 

-- 

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, 27 July 2007 16:27:13 GMT

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