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Re: Cool URIs, the Semantic Web and Everything

From: Ivan Herman <ivan@w3.org>
Date: Fri, 28 Dec 2007 09:27:09 +0100
Message-ID: <4774B35D.1010509@w3.org>
To: Richard Cyganiak <richard@cyganiak.de>
CC: Story Henry <henry.story@bblfish.net>, Michael Hausenblas <michael.hausenblas@joanneum.at>, Leo Sauermann <sauermann@dfki.uni-kl.de>, SW-forum Web <semantic-web@w3.org>
Just to make a small syntactic issue about RDFa clearer, it may help in
the discussion...

In RDFa, I can say:

<span about="#q" rel="bla:bla" resource="http://some.thing.here">...</span>

and that would yield, as expected

<THEBASEURI#q> bla:bla <ttp://some.thing.here>.

and it is *not* a requirement (as far as I know:-) that there must be an
XHTML element in the file with an @id="q".

Ivan

Richard Cyganiak wrote:
> 
> On 23 Dec 2007, at 22:31, Story Henry wrote:
> 
>> Why does id="i" have to refer to anything?
> 
> Well, the specs say so. The URI spec says that the meaning of hashy URIs
> depends on the MIME type of what you GET, and that each MIME type
> registration must say what hashes mean in that type. The XHTML
> registration says that #xyz designates the document part that has
> id="xyz". There you have it, that's the status quo. And I think it's a
> decent state of affairs.
> 
>> Why is it not just a behavioral specification that when displaying
>> html the page be move to that location if something like that is present?
> 
> To my knowledge, associating "behavioral specifications" with URIs is a
> new idea not currently found in web architecture. The current
> architecture seems to take the point of view that URI simply "identify"
> certain things; associating appropriate behaviour with those things is
> up to applications. I think that's a decent state of affairs.
> 
>> That would allow one to have a
>>
>> <http://sw-app.org/mic.xhtml#i> refer to a person, and also to have an
>> xhtml web page be showing the relevant part of the information.
>>
>> I am not sure the two need to be exclusive.
> 
> I agree, it's desirable that an RDFa URI <mic.xhtml#i>, if accessed in a
> web browser, automatically scrolls to the relevant part of the document.
> 
> But there are many ways to achieve that goal. Some good, some bad.
> 
> Adding id="i" to the document is a bad way, because it overloads the
> meaning of <mic.xhtml#i>.
> 
> Future RDFa-aware browsers could natively support this, by scrolling to
> the part of the document that carries the RDFa specification of the URI
> (e.g. an about="#i" attribute).
> 
> In the meantime, we could add a generic Javascript snippet to the
> document that automatically scrolls to id="definition_xyz" when #xyz is
> opened. This gives us the desired behaviour, while retaining different
> URIs for person and document section. (Yes, it's a hack.)
> 
> Merry Christmas to all!
> 
> Richard
> 
> 
> 
>>
>>
>> Henry
>>
>>
>> On 23 Dec 2007, at 13:25, Richard Cyganiak wrote:
>>
>>>
>>> This is impossible to answer, because the URI's configuration is
>>> broken. Even the author of the document seems to be confused about
>>> what he wants the URI to identify.
>>>
>>> There is an XHTML representation, and it has a id="i", which
>>> indicates that the URI identifies an XHTML fragment.
>>>
>>> But the XHTML document also encodes an RDF graph using RDFa. In it,
>>> the author tries to use the same URI to denote a person. He claims
>>> that a document fragment is a person. That's a nonsensical statement.
>>>
>>> Fortunately, this is easy to fix: Remove the id="i" from the
>>> document, or change it to a different ID, and everything is fine.
>>> After that fix, the answer would be 1, 2 and 6.
>>>
>>> Richard
>>
> 
> 

-- 

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, 28 December 2007 08:27:27 GMT

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