- 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
>>>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 UTC