W3C home > Mailing lists > Public > www-rdf-interest@w3.org > July 2001

rdf namespace reserved or not?

From: Jeremy Carroll <jjc@hplb.hpl.hp.com>
Date: Fri, 13 Jul 2001 18:46:28 +0100
Message-ID: <3B4F33F4.D0AF1C79@hplb.hpl.hp.com>
To: www-rdf-interest@w3.org
rdf:li AND rdf:_1 AS TYPES (reserving rdf: namespace)
==========================
rdf-containers-syntax-vs-schema/test005.rdf explicitly allows rdf:li and
rdf:_1 to be types.

<rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
         xmlns:foo="http://foo/">
  <rdf:_1/>
  <rdf:li/>
  <rdf:li/>
</rdf:RDF>

In contrast, in rdfcore/rdf-ns-prefix-confusion/test08.rdf the
rdf:aboutEachPrefix attribute is ignored.

Could you clarify what the correct processing of things from the rdf:
namespace is when they are not recognised or do not make sense.

The original spec gave clear instructions:

'When an RDF processor encounters an XML element or attribute name that
is declared to be from a namespace whose name begins with the string
"http://www.w3.org/TR/REC-rdf-syntax" [SIC] and the processor does not
recognize the semantics of that name then the processor is required to
skip (i.e., generate no tuples for) the entire XML element, including
its content, whose name is unrecognized or that has an attribute whose
name is unrecognized.'

In contrast, the intent of the Working Group seems to be that an RDF
processor should treat an unrecognised or not understood Qname from
rdf:XXX just like it would treat any other Qname (e.g. as a type or a
property). So that now rdf:aboutEachPrefix must be specially recognised
in order to be ignored!

I suggest that the original spec is a better intent - the rdf:XXX space
is reserved. It might be better to skip only the attribute in the case
of an unrecognised attribute; but I note that when a non-aboutEachPrefix
supporting processor meets and rdf:aboutEachPrefix attribute the
original behaviour of skipping the whole element is a good one.

I will give a few more corner cases:
<rdf:Description rdf:li="the only way to give an rdf:li value"/>
& what about

<rdf:Description rdf:Description="text string"/>

whereas presumably the insanely equivalent

<rdf:Description>
  <rdf:Description>text string</rdf:Description>
</rdf:Description>

is still an error.



Jeremy Carroll
HP Labs
Received on Friday, 13 July 2001 13:42:29 GMT

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