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Re: Treatment of RDFa in TAG Finding on Self-describing Web

From: Ben Adida <ben@adida.net>
Date: Wed, 10 Sep 2008 23:36:12 -0700
Message-ID: <48C8BC5C.3000500@adida.net>
To: Mark Baker <distobj@acm.org>
CC: noah_mendelsohn@us.ibm.com, Steven Pemberton <steven.pemberton@cwi.nl>, www-tag@w3.org


I think it's worth noting that this is RDFa in XHTML1.1, and that we
*have* (or at least have resolved to and will very soon) update the
XHTML namespace document to reflect how RDFa can and should be interpreted.

I believe that is the "missing link" in the reasoning, but please let me
know if I'm incorrect. I wanted to make sure this point was made before
Noah has to publish the TAG finding.

-Ben

Mark Baker wrote:
> Noah,
> 
> On Tue, Sep 9, 2008 at 5:52 PM,  <noah_mendelsohn@us.ibm.com> wrote:
>> * You then quote the RDFa Syntax and Processing draft: "There SHOULD be a
>> @version attribute on the html element with the value 'XHTML+RDFa 1.0;".
>> Let's for the moment ignore that it's a SHOULD and consider the case where
>> @version is indeed set this way.  Is there something in RFC 3236 or XHTML
>> 1.0 to the effect that "a value in the @version attribute of the HTML
>> element is a key that can be used to identify additional specification(s)
>> that provide normative interpretations for markup beyond that which is
>> standardized for XHTML itself?"  As best I can tell, XHTML delegates
>> discussion of the <HTML> element to HTML 4.01, and that in turn says that
>> the version attribute is deprecated! [1]  Is there something normative in
>> either XHTML or M12N that says "go looking for a specification that seems
>> to have been written by the authority responsible for the namespace used
>> in the new markup?".
>>
>> So, I'm still missing some crucial connections.=
> 
> I think there is one connection missing; RDFa extends the meaning of
> rel (and rev) attribute values in a manner which HTML doesn't licence.
> 
> Often, IME, doing that sort of thing is a really bad idea, but not
> always.  In this case, rel attribute values are a fairly simple
> element of HTML, as they're just a list of opaque strings from a small
> dictionary, and AFAIK, there's no processors which try to treat them
> as anything more than that.  So RDFa's introduction of special meaning
> to a colon - a character unused in that dictionary - is effectively
> harmless.
> 
> That's not the end of the story of course, because while RDFa isn't
> self-descriptive, it should be made so.  What that requires is an
> update to HTML to anoint the special meaning of ":" in link types;
> 
>  http://www.w3.org/html/wg/html5/#linkTypes
> 
> So for your draft, you might consider expanding 4.1 to explain in more
> detail what it means to extend an existing media type
> self-descriptively in both the short and long term.
> 
> Mark.
Received on Thursday, 11 September 2008 06:37:00 GMT

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