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[Moderator Action] Comments on CC/PP Structure and Vocabularies WD 15 March 2001

From: Kazuhiro Kitagawa <kaz@w3.org>
Date: Wed, 04 Apr 2001 02:00:36 +0900
Message-ID: <3ACA01B4.7000209@w3.org>
To: www-mobile@w3.org

I am commenting on
   Composite Capability/Preference Profiles (CC/PP): Structure and Vocabularies
   Working Draft 15 March 2001
   http://www.w3.org/TR/2001/WD-CCPP-struct-vocab-20010315/

from an RDF implementors point of view - RDF model and syntax
details, not the CC/PP application itself.

Firstly I'd like to second Dan Connolly's comments in

   http://lists.w3.org/Archives/Public/www-mobile/2001Mar/0006.html
   http://lists.w3.org/Archives/Public/www-mobile/2001Mar/0007.html

-  rdf:Property not rdfs:Property
-  the subclassing for ccpp:Value is the wrong way round
-  think about using XML schema definitions of some terms

I tried parsing http://www.w3.org/2000/07/04-ccpp.rdf with 6
different RDF/XML parsers and that worked OK giving the same answers.

I tried the example just at the end of section 1 and it failed on a
few parsers because the first element <RDF..> element should have
been <rdf:RDF>  Correct that caused most of them to work but the
stanford one failed - http://www-db.stanford.edu/~melnik/rdf/api.html

   => Don't assume that if it works with SiRPAC (W3C), it is correct :-)

Figure 2-1b: CC/PP profile components in XML

   Inconsistent use of rdf:about / about

   Get different answers here from different parsers (3 statements, 0
   statements, crash), but I suspect a conformance issue not anything
   else.

Figure 2-2b: Complete CC/PP profile example in XML

   No default namespace defined, but it is used for <display>
   etc. elements.  RDF parsing rules mean the entire content can be
   ignored so I suspect you need to add another xmlns:  The parsers
   accept this and generate illegal RDF statements with properties of
   the XML element names.


2.1.3 Defaults

Figure with no label, visually looks OK but examples 2-3 contain no
default xmlns so display etc. elements are not guaranteed to
generated RDF statements.

Figure 2-4b: Overriding a default value in XML

Ditto default xmlns in both examples

In 'Note' just at end; relative URIs can be used in RDF but not
recommended for namespaces - the latter is my opinion.

Section 2.2

Fragment:

----------------------------------------------------------------------
<?xml version="1.0"?>
<RDF xmlns="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
   xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
   xmlns:ccpp="http://www.w3.org/2000/07/04-ccpp#"
   xmlns:uaprof="http://www.wapforum.org/UAPROF/ccppschema-20000405#">
----------------------------------------------------------------------

Why are there two references to the RDF namespace?  This is strange
in the following sections since all rdf concepts are used and there
is no use of elements in the default namespace.

Maybe note that the namespace prefixes will change as the document
changes, and shouldn't be used in products blah blah like boilerplate
at the top.

2.3.1 Basic RDF Model

In definition of Resources it says "plus optional anchor ids" wheras
the box above uses #fragement-ID - make this consistent and change
any references to it.

Properties defn. section has reference [4] that isn't a hyperlink,
change that and references to Sections such as under defn. Statements
to be links.


Figure 2-9a: XML fragment containing RDF resource description

It may be a fragment but shouldn't those be <rdf:Description> blocks
like used all the previous examples?

Figure 2-10: RDF serialization

Has a different RDF header again, not like previous ones but similar
to the fragment in an earlier section.  Again use <Description> here
(and <type>) with default namespace versus <rdf:Description> in
previous examples

2.3.3 RDF schema

Can you add a link to the RDF schema document here since this is the
first discussion of it.

3.1.3 Defaults

In examples here using no rdf: prefixes on Description, type elements
or about, resource attributes.  So why declare xmlns:rdf ?

One note after an un-numbered figure says:

   [[NOTE: A default document uses a <Description> element as its root
   node. The <Description> is named using an about= attribute whose
   value is a URI. This URI MUST correspond to the value in the
   rdf:resource= attribute ...]]

however you don't use rdf:resource attribute in the example!


This kind of thing is used to label bare URIs:
  <http://www.w3.org/2000/07/04-ccpp-proxy#>
and although this is recommended by the URI spec, I suggest you add a
note somewhere early on explaining what this encoding means.

3.2.1 Capability chaining

examples back to rdf: everywhere agin


3.2.2.1 Example: XHTML to WML transcoding

has example with line
   <rdf:li>http://example.org/example/XHTML-1.0</rdf:li>
probably should be:
   <rdf:li rdf:resource="http://example.org/example/XHTML-1.0"/>
unless you wanted it as a string?


Appendixes

Can you add the URIs of all schema, attribute vocabulary documents
into the spec. near where they are textually included examples so
that it is clear what the included document is.

----------

Overall, need I say use consistent rdf: or not throughout?  I suggest
using rdf: everywhere and removing default namespace.  I this makes
the results too verbose, and it might, choose the other alternative -
no rdf: prefix and set it as the default namespace throughout.
I've been over this before in:
   http://www.redland.opensource.ac.uk/notes/concepts.html
which provides a ready reference for them.

Also, try a couple of RDF/XML parsers, you can do that at my demo
which I've been using here to try things out:
   http://www.redland.opensource.ac.uk/demo
or try some of the other online demos.  Maybe automate checking the
fragments and examples standalone and then build the document from
the bits? (after encoding in XHTML).

Add more links around document, make sure all figures and examples
have <a name> and captions/labels/numbers so they can be cited and
linked to in potential CC/PP validators.

Dave
Received on Tuesday, 3 April 2001 13:00:14 GMT

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