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RE: rdfms-literal-is-xml-structure: Why?

From: Ron Daniel <rdaniel@interwoven.com>
Date: Sun, 15 Jul 2001 08:13:29 -0700
To: "Brian McBride" <bwm@hplb.hpl.hp.com>
Cc: <connolly@w3.org>, "RDF Core" <w3c-rdfcore-wg@w3.org>
Message-ID: <EMEKICCGFEKJFGKMFLEPMEBKDBAA.rdaniel@interwoven.com>
Brian McBride said:

> What I think is needed here is that an RDF parser, when it encounters a
> parseType="Literal" would need to encode any active namespace prefix's
> in the literal representation, e.g.
> 
>   <rdf:Description xmlns:foo="http://foo">
>     <foo:property rdf:parseType="Literal">
>       <foo:bar>foobar</foo:bar>
>     </foo:property>
>   </rdf:Description>
> 
> its not enough for the literal just to represent "<foo:bar>foobar</foo:bar>".
> It must also represent xmlns:foo="http://foo".

I agree with the need to represent the namespace information.
I am not sure that we have to do it by encoding that
information directly into the literal. By that I assume you mean
the RDF processor would change the literal content from
  "<foo:bar>foobar</foo:bar>"
to something like
  "<foo:bar xmlns:foo="http://foo">foobar</foo:bar>

My personal preference would be to not rewrite that content if
we can avoid it. Also - since M&S 1.0 says we don't process
the content, we probably shouldn't process the content. Third,
that would be a backward-incompatible change and would
invalidate any current XML literals held in RDF databases.

Viewed abstractly, RDF processors must report a tuple of
(namespace initializations, literal XML content). This,
along with xml:lang, is missing from the M&S 1.0 model.

There are multiple APIs possible, the spec should not require
or preclude any particular one. However, we will have to
represent this information in the n-triples format in order to
test things.

Before we talk about the exact changes to the n-triples format
that we may make, we should agree on the info it must pass along.
(I don't want to let something like escape character considerations
influence the information we need to convey).

It seems that a record for a statement in the format must, at
a minimum, convey:
  subject  - an (absolute?) URI or URI reference
  predicate - an (absolute?) URI or URI reference
  object:
      an (absolute?) URI or URI reference
   OR a literal string, and
      a locale (xml:lang value, if given)
   OR a literal string,
      a parseType=Literal flag,
      a locale, and
      a set of namespace initializations   

Depending on our resolution of the aboutEach issue, we may
also need to add a flag to tell if the subject is simple or
an aboutEach.

Ron
Received on Sunday, 15 July 2001 11:15:16 EDT

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