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Re: moving forward!

From: Niklas Lindström <lindstream@gmail.com>
Date: Thu, 26 Jul 2007 00:33:05 +0200
Message-ID: <cf8107640707251533o392498b1x56a2cc16f5177e9e@mail.gmail.com>
To: "Ben Adida" <ben@adida.net>
Cc: RDFa <public-rdf-in-xhtml-tf@w3.org>


I'm sorry for my late post of this. I'll start with some hopefully
straightforward comments:

5) I'm ok with @src working like @resource. I believe this should work
so that @resource overrides @src (similar to how @content works).

4) I fully agree, still ;) (and trust that Ivan's comments regarding
@lang/@xml:lang are correct)

3) I think this very dependent on 1), but in general I like what I see
(and *really* hope that collection support like this can be worked
into the spec).

2) I like @instanceof. Not exclusively, as I explain in
but I still vote for it (unless convinced by more arguments).

Now, regarding 1). I find the current thoughts about striping very
appealing. Trying to match this with the current syntax, I come up
with the following questions:

== Striping ==

A. I want to interpret the rules given
to determine subject for nested content (i.e. corresponding RDF
identity) in a generalised way as:

    - If a relation (with @rel) to a resource is given, that object is
used as subject for nested content.
    - If that object is not explicit, a bnode is generated and used.
    - Unless the above, use the subject given in the element (by
@about, perhaps by @id - see [C] below).
    - If nothing of this applies, keep the current (inherited) subject.

Does this make sense?

B. Furthermore, I'm uncertain about what the resulting state should be
when @rev is used? Consider:

    <div about="#something" rev="dct:hasPart" resource="">

which AFAIK yields:

    <> dct:hasPart <#something> .

But what will the subject be for nested content? <#something> or <>?
Compare with this:

    <div rel="dct:hasPart" resource="something">

yielding the same triple as above, and according to the rules clearly
having <#something> as the "nested subject". This becomes even
trickier for me if both @rel and @rev is present, or if @resource is

C. Finally (perhaps digressing). If @id is to be used at all, I wonder
if @about should not have precedence over this (as opposed to the
proposed order of the rules referred to above). This to enable
explicit prevention of non-semantic @id:s to have significance. Still,
I suppose this is the subject for another discussion.

== The rdf:type shorthand ==

D. Regarding rdf:type, will this shorthand be a syntactic one based
upon the (above) subject striping rules? As opposed to another
resolution technique possibly directly affecting the striping

Assuming the former, is the rdf:type attribute (say @instanceof) a
plain shorthand for a child element with @rel="rdf:type" and a
@href/@resource? This must probably be the case, since if it is a
shorthand for putting the @rel etc in the same element, that would
make, by following the current idea of striping, the *type* the nested

Though, if @instanceof is a shorthand for a nested element doing the
typing, its presence would not make the element where it appears mean
anything for RDFa itself, e.g. generate any bnode (or eventual special
@id treatment), which *may* be desired..

That would also make @instanceof appearing alone strange (typing an
ancestor?). Because of this, perhaps a condition for the rdf:type
shorthand should be that a "corresponding RDF identity" resolution
must occur for the same element it appears in (otherwise either
yielding nothing or even be an error).

Or else it speaks for the latter case - a special rule both depending
on and affecting striping.

E. Finally, for future thought, does it seem reasonable that when this
attribute appears at the root element of a document (or even head in
XHTML), its xml:base (explicit or implicit) will be the subject of the
rdf:type statement? I suppose so (and that this works for either case

I sincerely hope these questions can be of relevance.

Best regards,

On 7/23/07, Ben Adida <ben@adida.net> wrote:
> Hi all,
> I suspect we're all hitting a little bit of spec fatigue. That said, we
> need to push through! We have one relatively important issue to cover
> (how striping really works), and a handful of smaller issues.
> So, *everyone* should take an action to think about and contribute
> thoughts on this list to the following issues, some time before Thursday.
> 1) Striping. @rel everywhere is hugely useful, but it does complicate
> things. Mark's latest description of what we should do:
> http://lists.w3.org/Archives/Public/public-rdf-in-xhtml-tf/2007Jul/0145.html
> and my proposed tweak with complete rules:
> http://lists.w3.org/Archives/Public/public-rdf-in-xhtml-tf/2007Jul/0158.html
> 2) the attribute name we should pick for rdf:type. It seems the only two
> real contenders so far are @instanceof, and @kind. I recently proposed
> @resourcetype, though haven't heard any feedback.
> Time to submit last suggestions including your top preference!
> 3) RDF containers and collections
> Last proposal and discussion:
> http://lists.w3.org/Archives/Public/public-rdf-in-xhtml-tf/2007Jul/0122.html
> http://lists.w3.org/Archives/Public/public-rdf-in-xhtml-tf/2007Jul/0131.html
> http://lists.w3.org/Archives/Public/public-rdf-in-xhtml-tf/2007Jul/0139.html
> 4) xml:lang
> We mentioned some solutions to this in the default datatype issue:
> http://lists.w3.org/Archives/Public/public-rdf-in-xhtml-tf/2007Jun/0039
> are we okay with the conclusion of this with respect to xml:lang?
> 5) The @src attribute on IMG. I think this one is pretty much done, but
> we need to resolve it:
> <img about="#me" rel="foaf:image" src="ben.jpg" instanceof="foaf:Image" />
> yields
> <#me> foaf:image <ben.jpg> .
> <ben.jpg> rdf:type foaf:Image .
> Any remaining issues on this for XHTML1.1+RDFa? I don't think so, but
> speak up if you do!
> -Ben
Received on Wednesday, 25 July 2007 22:33:09 UTC

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