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Re: capturing reserved keywords in @rel

From: Mark Birbeck <mark.birbeck@x-port.net>
Date: Tue, 22 Jan 2008 14:47:24 +0000
Message-ID: <a707f8300801220647i3541c6f4mcc60ed2dbb847f8d@mail.gmail.com>
To: "Ivan Herman" <ivan@w3.org>
Cc: "Ben Adida" <ben@adida.net>, RDFa <public-rdf-in-xhtml-tf@w3.org>

Hi Ivan,

> I do not think there should be _any_ reference to _any_ preprocessing
> step in RDFa. Yes, @rel="DC.Creator" will be lost...

Yes...that's exactly what I said, too. :) I'm not at all proposing
that we support other legacy values now, but I raised it because I
think we should somehow integrate our solution to the @rel value
problem into the general notion of @profile, rather than it being
something vague and non-XHTML.

So in XHTML, the spec already says that if you don't have a profile
for your @rel values, then unrecognised ones are ignored. I'm
suggesting that we leverage that by saying in a note that the
unrecognised values are actually discarded...we don't know how it's
done, but then the current HTML/XHTML documents don't say how it's
done either. :)

Now, we know in our 'meta world' sitting outside of the syntax
specification, that we _do_ actually know how the values will get
discarded -- we'll probably use a preprocessing step to do it. But
since we don't want to put that in the spec, the best we can do is put
a note into the spec that says something like:

  Normal @profile behaviour should still be observed, which means that @rel
  values that are not in the list of LinkTypes, and have not been made
  available via a profile, have no meaning. In an RDFa environment values
  in @rel that do conform to specified profiles should be treated as CURIEs,
  and placed into the appropriate namespace.

We don't say how to do this...we don't even mention a processor at
all. So for some implementers they might do this by doing the test
when processing @rel, others might do it like Ben has done, and run an
initial pre-processing step.

But the main point is that we have not changed the spec in relation to
CURIEs, and essentially the processing of @rel is no different to that
for @about. (It just so happens that certain kinds of values will
never reach the RDFa processor.)

Does that clarify what I'm getting at? The key thing is the note,
which needs to ensure that implementers know that something needs to
be done, but doesn't prescribe how, and at the same time, by referring
to @profile it is firmly grounded in existing XHTML concepts.



  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 Tuesday, 22 January 2008 14:47:32 UTC

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