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Comments on http://www.w3.org/TR/2008/WD-rdfa-syntax-20080221

From: Johannes Koch <koch@w3development.de>
Date: Tue, 26 Feb 2008 14:27:16 +0100
Message-ID: <47C413B4.5090603@w3development.de>
To: public-rdf-in-xhtml-tf@w3.org

Hi,

I have some comments on <http://www.w3.org/TR/2008/WD-rdfa-syntax-20080221>:

5.3. Chaining

The first code example

<div about="http://dbpedia.org/resource/Albert_Einstein">
   ...
   <img rel="foaf:depiction" 
src="http://en.wikipedia.org/wiki/Image:Albert_Einstein_Head.jpg" />

seems to indicate that a triple

<http://dbpedia.org/resource/Albert_Einstein>
   foaf:depiction
   <http://en.wikipedia.org/wiki/Image:Albert_Einstein_Head.jpg> .

should be created. But according to section 5.5 step 5 and section 
6.1.1.3 the rel attribute would have to be on the div element, not the 
img element. The example as is IMHO creates an incomplete triple

<http://en.wikipedia.org/wiki/Image:Albert_Einstein_Head.jpg>
   foaf:depiction
   ? .


5.5. Sequence

* step 5:
"Note that final value of the [current object resource] will either be 
null (from initialization), a full URI or a bnode."
According to the algorithm, [current object resource] is never set to a 
bnode.

* After step 8 follows step 10: Probably the numbering is incorrect.

* step 10 (9?):
"as a [plain literal] if:
   * @content is present;
   * or all children of the [current element] are text nodes;
   * or there are no child nodes;
   * or the body of the [current element] does have non-text child
     nodes but @datatype is present, with an empty value."
According to this the example in 6.3.1.2

<span property="cal:dtstart" content="20070916T1600-0500"
       datatype="xsd:datetime">
   September 16th at 4pm
</span>.

would not create a typed literal (@content is present). Or can the 
following bullets (XML literal, typed literal) "overwrite" the result 
from the first bullet (plain literal)?


6.1.1.5.2. Using an implicit object

second example:
<div about="http://dbpedia.org/resource/Baruch_Spinoza" 
rel="dbp:influenced">
   <div>
     <span property="foaf:name">Albert Einstein</span>
     <span property="dbp:dateOfBirth" datatype="xsd:date">1879-03-14</span>
   </div>
</div>

Because the inner div element has no instanceof attribute, according to 
section 5.5 step 4 [new subject] is set to the [evaluation context]'s 
[parent object], which is <http://dbpedia.org/resource/Baruch_Spinoza>, 
because the [current object resource] for the outer div was null.

The incomplete triple
   <http://dbpedia.org/resource/Baruch_Spinoza>
     dbp:influenced ? .
never gets completed. And because no bnode was created, the foaf:name 
and dbp:dateOfBirth properties apply to 
<http://dbpedia.org/resource/Baruch_Spinoza>.

Similar things happen with the third and forth examples in 6.1.1.5.2 and 
the sixth example in 6.2:

<div about="http://dbpedia.org/resource/Baruch_Spinoza" 
rel="dbp:influenced">
   <span property="foaf:name">Albert Einstein</span>
   <span property="dbp:dateOfBirth" datatype="xsd:date">1879-03-14</span>
   <div rel="dbp:citizenship">
     <span about="http://dbpedia.org/resource/Germany" />
     <span about="http://dbpedia.org/resource/United_States" />
   </div>
</div>


9.3. @rel/@rev attribute values

* While there is a "last" value listed, there is no "first".
* What about "top"?


A. Other XML Languages

"If a language includes @xml:base [XMLBASE], an RDFa parser for that 
host language must process it, and use its value to set [base]."
Is this a requirement? The section is marked "informative".

-- 
Johannes Koch
In te domine speravi; non confundar in aeternum.
                             (Te Deum, 4th cent.)
Received on Tuesday, 26 February 2008 13:27:32 GMT

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