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Comments on RDFa Syntax version 1.8 2007/04/06 16:36:34

From: Fabien Gandon <Fabien.Gandon@sophia.inria.fr>
Date: Thu, 12 Apr 2007 18:28:46 +0200
Message-ID: <461E5E3E.5060307@sophia.inria.fr>
To: public-rdf-in-xhtml-tf@w3.org

Hello,

To catch up with the RDFa work I reviewed the draft "RDFa Syntax: A
collection of attributes for layering RDF on XML languages" [1] in its
version 1.8 2007/04/06 16:36:34.
I hope to get time to update the RDFa2RDFXML transformation [2] to
reflect latest changes.

Below are some comments,

Cheers,

[1] http://www.w3.org/2006/07/SWD/RDFa/syntax/
[2] http://www-sop.inria.fr/acacia/soft/sweetwiki.html


Comment #1 - xml:base and produced triples
-------------------------------------------------------
Section 2.3 "Using xml:base" explains how to handle the about=""
http://www.w3.org/2006/07/SWD/RDFa/syntax/#id0x02576380

And the produced triples in the examples show the right URL for the document
<http://internet-apps.blogspot.com/>   dc:creator
<http://www.blogger.com/profile/1109404>

However in the other examples the code uses the "< >" notation which I
find confusing since they represent extracted triples and thus they
should refer to the document they were extracted from instead of using a
self-reference which is no longer correct if the triple is no longer in
its source document (see extracted triples in sections 2.2.1, 2.4, 3.4,
4.2.5, 4.3.3, 5.1.1, 5.3, 6.2). I think the URL of the document or its
base should always be explicit in the extracted triples especially since
this self-reference could be used to add metadata to extracted triples e.g.:

<photo1.jpg> dc:creator <http://www.blogger.com/profile/1109404> .
<http://www.blogger.com/profile/1109404> foaf:img <photo1.jpg> .
<photo1.jpg> dc:title "Portrait of Mark" .
<http://internet-apps.blogspot.com/> cc:license
<http://creativecommons.org/licenses/by/nc-nd/3.0/> .
< > dc:date "2007/04/12/"^^xsd:Date .


Comment #2 - namespace declaration
-------------------------------------------------------
The example in section 3.3 "Relating document components" declares only
the dc namespace.
http://www.w3.org/2006/07/SWD/RDFa/syntax/#id0x023295f8
In my opinion in this example, either you declare no namespaces at all
or you declare all the namespaces you use: taxo, rdf, biblio.

Moreover I think section 2.4 "Using CURIEs" should mention how the CURIE
prefixes are resolved to namespaces.


Comment #3 - Section 4.4 Establishing the subject
-------------------------------------------------------
http://www.w3.org/2006/07/SWD/RDFa/syntax/#id0x0255ad98
You wrote " At a high level, the subject of a statement is determined by
the about attribute, either on the element or on the closest parent of
that element. Two exceptions to that rule exist. First, if a closer
parent element includes a rel or rev attribute with no href, then the
subject is the CURIE/URI that corresponds to that parent element (as
described previously in object resolution.) Second, if the [RDFa
element] under consideration is a META or LINK without an about, then
the subject is the immediate parent element's CURIE/URI equivalent."

I found the use of "closet parent", "closer parent" and "immediate
parent" confusing I think the terminology of XPath axes "ancestor",
"parent", "child", "descendant", etc. ( http://www.w3.org/TR/xpath#axes
) is better and should be used in all the document as you did for
instance in section 4.4.2 "Inheriting the about attribute"
http://www.w3.org/2006/07/SWD/RDFa/syntax/#id0x0231be58


Comment #4 - Section 4.4.3 rel and rev attributes in ancestor elements
-------------------------------------------------------
http://www.w3.org/2006/07/SWD/RDFa/syntax/#id0x02547470

You wrote "During the ancestor element traversal, one may encounter an
element with a rel or rev attribute without a corresponding href
attribute. As described in object resolution, this situation defines a
new subject for all its children elements, in particular the currently
considered [RDFa element]. Specifically, the CURIE/URI associated with
this ancestor element becomes the subject."

So if I understand this well a node may become a subject when there is a
rel on it but couldn't we have the same case when it contains a link
element  ? I.e. could we have a case that looks like the following one
(I may have mixed up the syntax)

The following example:
<div about="album.html">
  <span rel="eg:finished">
     First page
   <span>This photo was taken by
     <span property="dc:creator">thomas</span>
   </span>.
</span>
</div>

Would produce:
<_:span0> eg:finished <_:span0>
<_:span0> dc:creator "thomas"^^rdf:XMLLiteral

While the following example the subject of dc:creator changes:
<div about="album.html">
  <span>
     <link rel="eg:finished" />
     First page
   <span>This photo was taken by
     <span property="dc:creator">thomas</span>
   </span>.
</span>
</div>

Would produce:
<_:span0> eg:finished < >
<album.html> dc:creator "thomas"^^rdf:XMLLiteral


Comment #5 - Section 5.3 Reification
-------------------------------------------------------
http://www.w3.org/2006/07/SWD/RDFa/syntax/#id0x031b2f98

You wrote "this document is licensed under a Creative Commons license,
and that "Ben Adida" is the creator of that licensing statement,"

I may be picky here but I think there is no formal link between the
licensing triple and the statement thus this is really saying that this
document is licensed under a Creative Commons license, and "Ben Adida"
is the creator of a statement saying that this document is licensed
under a Creative Commons license.

Ok, ok, this is a useless comment ;-)

-- 
Fabien - http://www.inria.fr/acacia/fabien/
Received on Thursday, 12 April 2007 16:29:21 GMT

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