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Re: A rose by any other name is just as thorny...

From: Sebastian Heath <sebastian.heath@gmail.com>
Date: Fri, 26 Mar 2010 09:48:51 -0400
Message-ID: <8347335f1003260648v7baf674i7c52200d357d021@mail.gmail.com>
To: RDFa WG <public-rdfa-wg@w3.org>
Junk triples concern me. I like that rel="foo" is ignored right now.
And I see room for odd decisions:

In a document with no @profile and no @vocab:

<a rel="foo" href="boo">I love foo.</a>

@about defaults to uri of current document. So subject of the triple is clear.

Predicate would be xhv:foo

 Object would be <full uri of document>/boo .

Or do browsers and rdfa parsers do different things with a relative
url, making the object xhv:boo ?

 -Sebastian



On Fri, Mar 26, 2010 at 9:34 AM, Manu Sporny <msporny@digitalbazaar.com> wrote:
> On 03/25/2010 05:02 PM, Ivan Herman wrote:
>> On 2010-3-25 15:11 , Shane McCarron wrote:
>> [skip]
>>>
>>> What's my point?  My point is this.  In a world where we permit the
>>> declaration of new default vocabulary prefixes, we have no need to ever
>>> determine the collection of terms that is defined by that vocabulary.
>>> We should just trust the document.  We are already doing that in every
>>> other instance anyway.
>>>
>>> Thoughts?
>>
>> I may either misunderstood you or the original proposal for the default
>> prefix. But _my_ understanding has always been that if one uses the
>> default vocabulary prefix than this is just used to be concatenated with
>> the prefix-less term in, say, @rel. That is certainly the way I
>> described in
>
> Shane's not talking about the "default-prefix" concept, at least, not
> directly. Shane is raising a very interesting point about the "default
> vocabulary" and how we might resolve keywords like prev/next.
>
> Namely, how do we mesh features like rel="prev" and rel="next" into the
> RDFa Core document without enforcing XHTML+RDFa keywords into RDFa Core?
> Remember, SVG, ODF, XHTML and HTML are all going to share the RDFa Core
> document - putting XHTML specific stuff into RDFa Core is far from ideal.
>
> We have been talking about a default vocabulary document for a couple of
> weeks now, the idea is that the default vocabulary document would be an
> RDFa Profile, and would be used if there is no mention of @profile in
> the current RDFa Processor context.
>
> So, at the moment, we could say that xhv is the URL for our default
> vocabulary document in RDFa 1.0:
>
> http://www.w3.org/1999/xhtml/vocab#
>
> and when somebody does this RDFa 1.0:
>
> <body>
>   <a rel="next" href="chapter3.html">Chapter 3</a>
> </body>
>
> We create this triple:
>
> <>
>   <http://www.w3.org/1999/xhtml/vocab#next>
>      <chapter3.html> .
>
> That's hardcoded into all the RDFa Processors right now. Shane is
> saying, let's not hard-code it and let's not require de-referencing the
> default RDFa Vocabulary Document (http://www.w3.org/1999/xhtml/vocab#).
> Like Toby's line of argumentation, a processor doesn't need to
> dereference the default RDFa Vocabulary document to generate a triple.
> For example, in RDFa 1.1 - if there is no active @profile, and there is
> no active @vocab, this markup:
>
> <body>
>   <a rel="foo" href="bar.html">Baz</a>
> </body>
>
> would generate this triple:
>
> <>
>   <http://www.w3.org/1999/xhtml/vocab#foo>
>      <bar.html> .
>
> Yes, "foo" isn't defined in the XHTML vocabulary, but who cares? It's
> not going to do anything if generated... it's a useless triple.
> Historically, we've shyed away from this behavior in the name of not
> generating junk triples. It's the reason we put all of the reserved
> words in a normative section in the RDFa 1.1 spec.
>
> ****
> So, Shane is saying - let's relax this requirement and not specify
> reserved keywords in the RDFa specification. Let's just specify a
> default vocabulary URL.
> ****
>
> If we do that, we simplify the spec and don't require dereferencing of
> the default vocabulary document. The downside is that we run the risk of
> generating junk triples. The bottom line, though - is that there is
> still a follow-your-nose story. The RDFa processor should trust that
> what the author put in the document is what they meant.
>
>> http://www.w3.org/2010/02/rdfa/drafts/2010/ED-vocab-20100326/
>>
>> There is no intention of dereferencing that URI.
>
> Yes, for @vocab... but we're not talking only about @vocab. We're
> talking about the interplay between "The Default RDFa Vocabulary" (which
> is an RDFa Profile), @profile and @vocab. So, something like this:
>
>   <a rel="foo" href="bar.html">Baz</a>
>
> would follow these rules in Shane's "rose" proposal:
>
> 1. If there is a @vocab active in the current RDFa Processor context,
>   generate a triple with @vocab + foo as the predicate.
> 2. If there is no @vocab active, but there is a @profile active check:
>   2.1 If "foo" is a keyword defined by @profile, and if so
>       use that URL.
>   2.2 If "foo" is not a keyword defined by @profile, generate a
>       triple with xhv + foo as the predicate.
> 3. If there is no @vocab or @profile active in the current RDFa
>   Processor context, generate a triple with xhv + foo as the predicate.
>
> At least, I think that's what Shane is saying...
>
> -- manu
>
> --
> Manu Sporny (skype: msporny, twitter: manusporny)
> President/CEO - Digital Bazaar, Inc.
> blog: PaySwarming Goes Open Source
> http://blog.digitalbazaar.com/2010/02/01/bitmunk-payswarming/
>
>
Received on Friday, 26 March 2010 13:49:25 GMT

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