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Re: Need volunteer reviewers for RDFa Core 1.1 (pre-Last Call)

From: Christoph LANGE <ch.lange@jacobs-university.de>
Date: Tue, 19 Oct 2010 00:51:49 +0200
To: Shane McCarron <shane@aptest.com>
Cc: Manu Sporny <msporny@digitalbazaar.com>, RDFa WG <public-rdfa-wg@w3.org>
Message-Id: <201010190052.03895.ch.lange@jacobs-university.de>

  thanks for your detailed feedback.  I really appreciate the transparent way in which you addressed Gregg's and my review.

Some comments follow below.  Generally, where I didn't comment: Thanks for your explanations!  They helped me to understand the things that had been unclear to me.  (And the unclarities were not always to blame on the spec text!)

Monday 2010-10-18 23:02 Shane McCarron:
> On 10/11/2010 6:53 PM, Christoph LANGE wrote:
> >> RDF/XML … validate … Schema
> > I don't think that _that_ paragraph is really necessary to motivate RDFa.  RDFa can't be validated by those means either.
> Sure it can.  Or rather, we provide the infrastructure so that Host 
> Languages that include RDFa can support validation if their authors 
> choose to make that service available.

You are right – I was misled into thinking of a higher level of validation, i.e. RDFS or OWL validation, such as checking whether properties are used in compliance with their rdfs:domain or rdfs:range.  So if you mean by validation that, e.g., @about should be allowed on every element of the host language, and that it should have a SafeCURIEorCURIEorURI value – that's possible for sure, and indeed you provide the infrastructure for that.

> > (!) A comment for future discussion: Would it make sense to specify an algorithm for "normalizing" a fragment?  I mean making it self-contained, so that it can be pasted somewhere else.
> This is a good idea!  I am not going to try to come up with that for 
> last call.  However, see the new note in Sequence step 11.  Does this 
> start to get where you want to be?

Is the new version (editor's draft?) already available online?  I couldn't find it.

> > 4.2 RDFa Host Language Conformance
> >> If the Host Language uses XML Namespaces [XML-NAMES], the attributes in this specification should be incorporated in the namespace of the Host Language.
> > He had a discussion about that last week or so.  What does that mean?  Suppose the namespace of the host language is xmlns:h="http://host.org".  Should the RDFa attributes be used as<h:element h:about="URI"/>, or as<h:element about="URI"/>?  The latter (i.e. putting attributes into the empty namespace) is what, according to Toby, all currently existing host languages do.
> Actually, this language is a mistake.  My mistake.  The intent of that 
> language, which I have used in lots of specifications, is that when the 
> attributes are used you don't need to use them with a prefix.  I have 
> fixed the text.

That sounds good to me.  IMHO the root of the misunderstanding is that the XML designers put unprefixed attributes into the empty namespace, and not, as unprefixed elements, into the default namespace – but that's something that we can't change any more.

> ...
> The rdfa attributes are currently defined in the XHTML namespace - and I 
> think it is adequate that they stay there.

I agree with that.  The concerns that I had w.r.t. the attributes are adequately addressed that way.

So, just to get it right – is the following reasoning correct?

Suppose a host language H declares an attribute that has the same name as one of the RDFa attributes, let it be @about, in a way that is not compatible with RDFa.  Then, would the "H+RDFa" specification have to require the RDFa attributes to be in the XHTML namespace, so as not to collide with H's own attributes?  If so, I guess the following fragment of a H document would not generate any triples:

<host-element about="foo" rel="bar" resource="baz"/>

… because these are considered attributes of the H language, whereas …

<host-element xmlns:rdfa="http://www.w3.org/1999/xhtml"
  rdfa:about="foo" rdfa:rel="bar" rdfa:resource="baz"/>

… would generate the triple (foo, bar, baz).

(Note that I took the freedom to bind the "rdfa" prefix to the XHTML namespace URI; I think that's more intuitive, provided that the host language doesn't have any relation to XHTML.)

> > 7.3 Chaining
> >> Federal Republic of Germany
> > This example is flawed.  At the time Einstein was born, "Germany" was not called "Federal Republic of Germany", but "German Empire".  However, the DBpedia article "Germany" describes Germany as it is now, i.e. the Federal Republic of Germany.  I'd suggest to circumvent such temporal issues by taking a person born in a different country, or a (West) German born after 1949 ;-)
> I changed all the examples to cite the German Empire.  And that was a 
> massive pain in the butt.

Sorry about the pain.  Now that the spec can no longer be misinterpreted as to Einstein being born in the Federal Republic of Germany, I will stop nitpicking about that :-)

IMHO the remaining part of the problem (if anyone else should nitpick) is definitely with Wikipedia/DBpedia, which identifies a country in general (i.e. throughout its whole history) with the legal entity it corresponded to, w.r.t. international law, at the time the Wikipedia article was last updated.



Christoph Lange, Jacobs Univ. Bremen, http://kwarc.info/clange, Skype duke4701

Received on Monday, 18 October 2010 22:52:18 UTC

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