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Re: rdfms-syntax-incomplete

From: Dan Connolly <connolly@w3.org>
Date: 18 Jul 2002 10:08:03 -0500
To: Jeremy Carroll <jjc@hplb.hpl.hp.com>
Cc: w3c-rdfcore-wg@w3.org
Message-Id: <1027004884.27663.248.camel@dirk>

preface: I remain opposed to re-opening this issue,
on the grounds that we've slipped considerably
since our "last call in May" target, and this
represents more stuff between us and last call.

Has the issue been reopened? evidently so, from
12: Representing B-nodes in the graph syntax
http://lists.w3.org/Archives/Public/w3c-rdfcore-wg/2002Jul/0081.html

OK, having crossed that bridge...
as an implementor, I find this appealing;
it addresses a known problem with the SWAP tools...

Currently, the SWAP tools, when given...

  _:a <#prop> _:a.

write the following, which is clearly horked:

<rdf:RDF xmlns="file:/dev/stdin#"
    xmlns:log="http://www.w3.org/2000/10/swap/log#"
    xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#">

    <rdf:Description rdf:about="#0_work">
        <log:forSome rdf:resource="#_ga"/>
    </rdf:Description>

    <rdf:Description rdf:about="#_ga">
        <prop rdf:resource="#_ga"/>
    </rdf:Description>
</rdf:RDF>

[using log:forSome as a property is nonmonotonic,
even after you squint really hard to see how
cwm uses it.]

I gather that if we adopt this, it would/could write:

<rdf:RDF xmlns="file:/dev/stdin#"
    xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#">

    <rdf:Description rdf:node="ga">
        <prop rdf:resource="ga"/>
    </rdf:Description>
</rdf:RDF>


which would communicate, in an interoperable manner,
just what the original form meant.


I'd feel better about it if I found time to implement
it, but I'm reasonably confident it's sound.

Some details:

On Tue, 2002-07-16 at 13:48, Jeremy Carroll wrote:
> 
> 
> Proposal in brief:
> 
> - use attribute rdf:node to associate node identifiers with blank nodes.
> - file scoped identifier.
> - any XML string is legal blank node identifier.

XML IDs would be easier for me to support.

> Full resolution:
> - reopen issue rdfms-syntax-incomplete

We're still debating whether to reopen it? Seems to
me that in assigning you this action, the group decided
to re-open it. Maybe not. Who cares...

> - add an attribute rdf:node to the RDF/XML syntax.

I don't like the name. I don't know why.

thinking out loud...

  rdf:term
	nah... that's meta-syntax
  rdf:something
	too long, goofy
  rdf:some
	hmm... maybe I like that...

	<rdf:Description rdf:about="some/doc">
	  <dc:creator rdf:some="party"/>
	  <dc:publisher rdf:some="party"/>
	</rdf:Description>

	hmm... kinda sounds like rdf:type...


OK, rdf:node is as good as anything I can come up with.


> - modify the syntax to permit rdf:node in place of rdf:about.
> - such a use associates the value of the attribute as a file scoped
> identifier for the blank node
> - modify the syntax to permit rdf:node in place of rdf:resource.
> - such a use associates the value of the attribute as a file scoped
> identifier for the blank node
> - any two blank nodes arising from the same RDF/XML file with the same
> identifier are the same blank node
> - action syntax editor to update the document to reflect this
> - rdf:node is not permitted as an element name in RDF/XML
> - action jjc to produce test cases
> - action daveb to update rdfms-names-use to reflect rdf:node
> - close issue
> 
> 
> ======
> 
> The chair was keen that we avoid too much discussion. I would like to
> highlight the choicepoints.
> 
> + use of attribute rather than pseudoURI

yeah verily.

> 
> One possibility was to use "_:label" in place of urirefs on the rdf:about
> and rdf:resource attributes. People said they did not like this idea. It
> would have less clarity but greater backward compatibility.
> 
> + use of file scope rather than global scode node identifiers

yeah.

> 
> The scope of the identifiers is the same as the scope of identifiers in
> N-triples, i.e. the file. Some use cases point to a need for global scope
> blank node identifiers (e.g. talking about a node within a graph for later
> updates to the graph). This seems to me to be a separate issue, and
> addressing it would constitute a greater change to RDF. (global scope  means
> world-wide, like uris).
> 
> + use of one attributes for both subject and object position rather than
> two.

no opinion.

> 
> The current syntax uses two attributes for URI refs. rdf:about on typed
> nodes and descriptions and rdf:resource on property elements. Since these
> two contexts are distinct there is no ambiguity in using the same attribute
> name for both. It may be less confusing to have rdf:aboutNodeIdentifier and
> rdf:resourceNodeIdentifier for the two different roles.
> 
> + choice of a short attribute name
> 
> rdf:node seemed about the shortest clear name for the attribute.

see above.

> 
> 
> 
> Jeremy
> 
> 
> 
> 
-- 
Dan Connolly, W3C http://www.w3.org/People/Connolly/
Received on Thursday, 18 July 2002 11:09:00 EDT

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