Re: Evaluations of Test Cases 46-56

Hi Manu,

You wrote:
> [snip]
>
> So, just to clarify:
>
> If @rel is specified and @resource is specified, the @instanceof is
> applied to the subject set by @resource (TC47).
>
> If @rel is specified but @resource and @about is not specified, the
> @instanceof creates a new bnode and specifies that as the active @about
> for the @rel (TC48)?
>
> It seems like we're saying if you do this:
>
> <div about="http://www.example.org" instanceof="foaf:Person">
>
> then you get this:
>
> <http://www.example.org> <rdf:type> foaf:Person
>
> but if you do this:
>
> <div about="http://www.example.org" instanceof="foaf:Person"
>      rel="foaf:knows" resource="#foo">
>
> then you get this:
>
> <http://www.example.org> <foaf:knows> <#foo>
> <#foo> <rdf:type> foaf:Person
>
> That is confusing to me. It feels like we're changing the meaning of
> @about/@instanceof when they are used together based on whether or not
> @rel and @resource exist. When we use @about and @instanceof in the same
> element, the same thing should always happen... @instanceof should be
> applied to @about.
>
> What am I missing? It feels like I'm missing something fundamental.

Your interpretation is exactly right of what Ben is saying, but the
behaviour of @instanceof with 'chaining' remains one of the final
couple of issues that we need to resolve.

Now, just in case people are worrying when they see words like "issue"
and "need to resolve"... :)

All other uses of @instanceof have been nailed down; the only issue we
are still discussing is what should happen when @instanceof is used
with @rel and @about at the same time. So we're really talking about a
very specific use-case, and not some general problem.

I should add though, that seeing your example just made me realise
that for Ben's rules to be consistent, any @property values should
also be attached to the 'second-level' subject:

  <div
   about="http://www.example.org"
     rel="foaf:knows"
       resource="#foo"
         instanceof="foaf:Person"
         property="foaf:name" content="Manu"
  />

  <http://www.example.org> <foaf:knows> <#foo> .
  <#foo> <rdf:type> foaf:Person .
  <#foo> <foaf:name> "Manu" .

I find that very confusing, I'm afraid. However, if in this model we
were to say that @property were to apply to @about (in just the same
way that @rel does):

  <div
   about="http://www.example.org"
     property="foaf:name" content="Manu"
     rel="foaf:knows"
       resource="#foo"
         instanceof="foaf:Person"
  />

then it makes it even more confusing that @instanceof is the only
attribute that has its behaviour changed in this way.

Regards,

Mark

-- 
  Mark Birbeck, formsPlayer

  mark.birbeck@formsPlayer.com | +44 (0) 20 7689 9232
  http://www.formsPlayer.com | http://internet-apps.blogspot.com

  standards. innovation.

Received on Thursday, 18 October 2007 11:17:36 UTC