W3C home > Mailing lists > Public > www-rdf-comments@w3.org > April to June 2003

Re: [closed] Re: buglet in syntax / test cases

From: Dave Beckett <dave.beckett@bristol.ac.uk>
Date: Fri, 6 Jun 2003 13:51:55 +0100
To: "Peter F. Patel-Schneider" <pfps@research.bell-labs.com>
Cc: www-rdf-comments@w3.org
Message-Id: <20030606135155.2a913f21.dave.beckett@bristol.ac.uk>

On Wed, 04 Jun 2003 12:43:18 -0400 (EDT)
"Peter F. Patel-Schneider" <pfps@research.bell-labs.com> wrote:

> From: Dave Beckett <dave.beckett@bristol.ac.uk>
> Subject: Re: [closed] Re: buglet in syntax / test cases
> Date: Wed, 4 Jun 2003 16:38:24 +0100
> 
> > On Wed, 04 Jun 2003 10:39:24 -0400 (EDT)
> > "Peter F. Patel-Schneider" <pfps@research.bell-labs.com> wrote:
> > 
> > > The issue is that RDF/XML mandates special treatment of certain items in
> > > an XML info set, namely attributes of a certain form.  There is no
> > > justification for this special treatment.  
> > 
> > All applications of XML define application-specific treatment of XML
> > items for their own use.  This requires no "special treatment" or justification.
> 
> Huh?  How is the removal of certain attributes not special treatment?

The non-interpretation of things that XML says is reserved is good practice.
If RDF/XML had defined meaning for these XML-reserved things, that would
have been wrong.

> > > It appears that the special treatment is related to the notion of reserved
> > > names in XML, but the RDF special treatment does not match the notion of
> > > XML reserved names.
> > 
> > It matches it fine.
> 
> On the contrary, there is much divergence.  See below for more details.

No.

> > > If the justification for the special treatment is to remove XML reserved
> > > names from the resultant RDF graph, then the treatment should be adjusted
> > > to match the XML treatment, *and* the rationale should be mentioned.  If
> > > the justification is something else, then this rationale should be
> > > mentioned and defended.
> > 
> > There is neither special treatment, nor RDF/XML doing anything usual
> > with 'xml'-prefixed names.  It exactly matches the XML specification -
> > they are reserved for the XML (family of) specification(s) to deal with
> > and we take care to preserve that.
> > 
> > Dave
> 
> I am completely mystified as to how you can possibly make this false
> statement.

I will annotate your comments to show you again where you went wrong.

> >From http://www.w3.org/TR/REC-xml, Section 2.3
> 
> 	[Definition: A Name is .... Names beginning with the string "xml",
> 	or any string which would match (('X' | 'x') ('M' | 'm') ('L' |
> 	'l')), are reserved for standardization in this or future versions
> 	of this specification.]
> 
> Hmm.  I guess, then that the name XMLnewname is not reserved.  Strange.

No, XMLnewname matches names beginning with (('X' | 'x') ('M' | 'm') ('L' | 'l'))

> 
> >From http://www.w3.org/TR/REC-xml, Section 3
> 
> 	[39] element ::= EmptyElemTag | STag ...
> 
> 	[40] STag ::= '<' Name (S Attribute) * ...
> 
> 	[41] Attribute ::= Name ...
> 
> 	[44] EmptyElemTag ::= '<' Name (S Attribute) * ...
> 
> >From http://www.w3.org/TR/xml-names11/, Section 3
> 
> 	The prefix xml is ...
> 
> 	The prefix xmlns is ...
> 
> 	All other prefixes beginning with the three-letter sequence x, m,
> 	l, in any case combination are reserved.  This means that 
> 	- users should not use them except as defined by later
> 	  specifications.
> 	- processors must not treat them as fatal errors.
> 
> 	Though they are not themselves reserved, it is inadvisable to use
> 	prefixed names whose LocalPart begins with the letters x, m, l, in
> 	any case combination, as these names would be reserved if used
> 	without a prefix.
> 
> Hmm.  This is slightly inconsistent with http://www.w3.org/TR/REC-xml,
> Section 2.3. 

Problems with XML specifications belong with the XML comments lists
attached to each of the documents.

> >From http://www.w3.org/TR/rdf-syntax-grammar/, Section 6.1.2
> 
> 	If the value contains an attribute event xml:lang (that is ... and
> 	the namespace name accessor of the attribute has value
> 	"http://www.w3.org/XML/1998/namespace") ... it is removed from the
> 	list of attributes ...
> 
> 	All other attributes beginning with xml are then removed (that is,
> 	all attributes with namespace name accessors beginning with
> 	"http://www.w3.org/XML/1998/namespace"). ...
> 
> The two criteria in the paragraphs above are not equivalent.
> 
> (I note also that the incorrect namespace is used in both places.)

No - the correct namespace is used in both places.


> This ends up with the following status under the following namespace
> declarations
> 	xmlns:xmlxxx="http:http://www.w3.org/XML/1998/namespace"
> 	xmlns:xMlxxx="http:http://www.w3.org/XML/1998/namespace"
> 	xmlns:xxx="http:http://www.w3.org/XML/1998/namespace"

All of the above are, I assume, intended to be
"http://www.w3.org/XML/1998/namespace" in which case they are illegal
Namespaces in XML.  You cannot define additional prefixes for the XML
namespace name.  This is in the XML specifications.


> 	xmlns:bar="ex://ex/"
> 
> 
> Name		XML treatment	XML namespaces	Special treatment in XML/RDF
> 		in both 	treatment in	*when used as an attribute name*
> 		attribute and	both attribute	1st criterion	2nd criterion
> 		element names	and element 
> 				names
> 
> xML		reserved	not addressed	no		no
> xmlxx		reserved	not addressed	yes		no
> xMLxx		not reserved	not addressed	no		no
> xmlxxx:bar	reserved	reserved	yes		yes
> xMlxxx:bar	not reserved	reserved	no		yes

all reserved by XML

> xxx:bar		not reserved	not reserved	no		yes

RDF/XML does tell you what to do with what XML doesn't
reserve, that's the whole point of XML syntaxes.

> xmlxxxbar	reserved	not addressed	yes		no
> xMlxxxbar	not reserved	not addressed	no		no

all reserved by XML

> bar:xmlxxx	not reserved	inadvisable	no		no
> bar:xMlxxx	not reserved	inadvisable	no		no

This is OK since RDF/XML requires namespaced names for these cases so
the inadvisable case is unlikely to happen and anyway it is not
required to reserve these.


You have brought up no issue on the RDF/XML syntax specification from
this thread and your confusions mostly are from your readings of the XML
specifications.

(The other thread on reserved namespace URIs is being dealt with there).

I am not required to have to teach you these XML and layering
fundamentals which can be found by reading the XML specifications
properly.

This is not a discussion list.  Please can you take your XML
questions to another forum such as xml-dev, questions on XML
documents to the authors, editors or coments lists for those
documents and if you want to discuss RDF, use www-rdf-interest.

Thanks

Dave
Received on Friday, 6 June 2003 08:52:44 GMT

This archive was generated by hypermail 2.2.0+W3C-0.50 : Friday, 21 September 2012 14:16:32 GMT