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Re: Issue rdfms-rdf-names-use

From: Dave Beckett <dave.beckett@bristol.ac.uk>
Date: Wed, 21 Nov 2001 21:04:23 +0000
To: Brian McBride <bwm@hplb.hpl.hp.com>
cc: w3c-rdfcore-wg@w3.org
Message-ID: <30494.1006376663@tatooine.ilrt.bris.ac.uk>
>>>Brian McBride said:
> I got the following example from Roland Schwaenzl
> 
> Apparently, they use the fact that an RDF parser is required to turn of 
> parsing when it encounters a name in the RDF namespace it does 
> recognise.

<snip/>

The existing M&S is rather vague on this point IMHO:

  "The RDF element is a simple wrapper that marks the boundaries in an
  XML document between which the content is explicitly intended to be
  mappable into an RDF data model instance. The RDF element is
  optional if the content can be known to be RDF from the application
  context."
  -- 2.2.1. Basic Serialization Syntax
     http://www.w3.org/TR/1999/REC-rdf-syntax-19990222/

since context is never defined. and in the grammar:

   [6.1] RDF ::= ['<rdf:RDF>'] obj* ['</rdf:RDF>']

   -- http://www.w3.org/TR/1999/REC-rdf-syntax-19990222/#RDF

and thus rdf:RDF is actually entirely optional in the grammar.


We could specify it clearer in several ways.

I've currently got these words in my editors draft:

  If the content is known to be RDF/XML by context, such as when
  RDF/XML is embedded inside other XML content, then the grammar can
  either start at Element Node RDF (only when an element is legal at
  that point in the XML) or at production nodeElementList (only when
  element content is legal, since this is a list of elements). Note
  that if such embedding ocurrs, the grammar may be entered several
  times but no state is expected to be preserved.

  http://ilrt.org/discovery/2001/07/rdf-syntax-grammar/#section-Infoset-Grammar

This gets around another issue - the XML infoset upon which this is
based is not defined for namespaced XML elements / attributes, so we
can't actually deal with them at all in the regular grammar:

  XML 1.0 documents that do not conform to [Namespaces], though
  technically well-formed, are not considered to have meaningful
  information sets. That is, this specification does not define an
  information set for documents that have element or attribute names
  containing colons that are used in other ways than as prescribed by
  [Namespaces].
  -- http://www.w3.org/TR/2001/REC-xml-infoset-20011024/#intro


so for Rolands example, the current wording allows his application to
enter/leave RDF processing at the rdf:RDF element; and we don't and
shouldn't define what is outside that.
 
Dave
Received on Wednesday, 21 November 2001 16:07:36 EST

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