Re: thoughts on @resource in current RDFa Syntax draft

Mark Birbeck wrote:
> Hi Ivan,
> 

> 
>> The problem I see is the @href/@resource situation. Remember that @href
>> and @resource behave almost identically except for the priority and the
>> usage of CURIE-s (we actually had to discuss whether we would have
>> @resource at all!).
> 
> Actually, we used to have @resource, and @href wasn't used at all. It
> took Ben a while to convince me to find a way to drop @resource in
> favour of @href, but of course he was exactly right (his famous
> 'bridging the clickable and semantic webs' argument was the clincher).
> The more recent discussion you are referring to was about supporting
> both attributes (or in effect, restoring @resource).
> 
> (I know, I know...you're not interested in the history. :) I'm only
> pointing this out because you're reminding me of an old discussion,
> and I'm just pointing out that there is an even older one.)
> 

Nothing to do with RDFa... I have written a blog during vacations:

http://ivanherman.wordpress.com/2007/12/26/very-deep-is-the-well-of-the-past%e2%80%a6/

which used a quote of Thomas Mann:

“Very deep is the well of the past. Should we not call it bottomless?”

This seems to be the case for RDFa, too:-)

> 
>> So I would expect you'd assign the same behaviour to
>> @href, too. But look at the following
>>
>> <div about="#A" rel="a:b">
>>    <a href="http://some.where">Something</a>
>>    <span rel="some:else" resource="#C"/>
>> </div>
>>
>> My expectation is that the following would be generated
>>
>> <#A> a:b [ some:else <#C> ].
>>
>> However, if I followed your logic, then the
>>
>> <#A> a:b <http://some.where> .
>>
>> triple would also be added.
> 
> Yes...definitely. That's the goal. Just so that I understand you, if
> you replaced @href with @resource in your example:
> 
>   <div about="#A" rel="a:b">
>     <span resource="http://some.where">Something</span>
>     <span rel="some:else" resource="#C"/>
>   </div>
> 
> are you suggesting that you would still get *only* this:
> 
>   <#A> a:b [ some:else <#C> ].
> 

Yes.

> That goes against the whole 'hanging rel' or 'incomplete triple' thing
> that I've been arguing for, and that I thought we'd all agreed on.
> 

Well... that was not my understanding. My understanding was/is that 
hanging rels are 'instantiated', so to say, if they are filled up via an 
explicit @about, a @src (per Ben's proposal), an @instancof BNode (per 
the discussion that ended around XMas) or by the BNode generated by the 
element with hanging rels in case there is another @rel/@rev down the 
line that follows the chain. As far as my understanding goes, there is a 
full stop there...

At least it seems to be clear where we disagree. My *impression* is that 
Ben's understanding is the same as mine... ie, this must be decided by 
the group...

> 
>> My feeling is that this is wrong: the user
>> uses <a> in the good old way, regardless of RDFa, and through the
>> approach you have in mind this cannot be done... unless suddenly
>> @resource has a very different behaviour than @href.
> 
> I'm not with you. In my approach they are exactly the same--you seem
> to be saying that @href and @resource should behave differently, not
> me. (I'm sure I'm misunderstanding that last comment, so please
> clarify.)
> 

Well, with my understanding @resource and @href do behave identically 
(priority and CURIE issues aside)

Cheers

Ivan

> 
>> I do not want to comment on the rest of the mail because, I think that
>> is the crucial issue, the rest somehow may follow.
> 
> I'm not sure it is. This issue at least, seems to be resolved to me,
> but perhaps I've missed something.
> 
> Regards,
> 
> Mark
> 

-- 

Ivan Herman, W3C Semantic Web Activity Lead
Home: http://www.w3.org/People/Ivan/
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