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Re: Saying anything about anything: Comments on Harle & Fensel

From: Gabe Beged-Dov <begeddov@jfinity.com>
Date: Thu, 06 Jan 2000 07:45:56 -0800
Message-ID: <3874B8B4.A832CA80@jfinity.com>
To: "Ralph R. Swick" <swick@w3.org>
CC: www-rdf-interest@w3.org, "Henry S. Thompson" <ht@cogsci.ed.ac.uk>, xml-schema-comments <www-xml-schema-comments@w3c.org>
"Ralph R. Swick" wrote:

> This is standard O-O stuff.  Part of your complaint has to do
> with naming; in RDF all names have global scope.  But as Jonas
> Liljegren properly reminds us in
> http://lists.w3.org/Archives/Public/www-rdf-interest/2000Jan/0014
> the true name of an RDF property is a full URI.  Just as in
> any O-O system -- it seems to permit you to reuse names across
> classes but the fully qualified name is actually constructed
> using additonal information such as the class hierarchy.
> While most O-O systems have a syntactic convience that allows,
> e.g., "this->" to be omitted, the fully qualified name for a
> class method or variable is always unambiguously defined.
> Such naming conveniences have a lot to do with the syntax in
> which expressions are written.  XML does not (yet) have the
> sorts of name constructors that O-O systems have.  XML
> Namespaces are the closest thing provided by XML -- and the
> RDF XML encoding uses them heavily.  Putting the class
> qualification into the namespace URI is a simple transformation
> and precisely matches the usage in traditional O-O systems.

My primary approach to mapping OO stuff to XML is to
use a namespace for each class and place the
properties/variables/accessors in the same namespace.
As you say later in your message, the power of RDF is
that it allows both the definition and the use of these
"accessors" to be made at a separate location from the
definition/use of the class. You then use the namespace
to create the binding between the class and the
accessors rather than lexical containment. 

XML Schemas focuses on lexical containment for the
definition/use of classes and their accessors. I was
assuming that locally scoped types would have the same
namespace as their class but a recent exchange on the
xml-schema-comments list [1] indicates that this isn't
the case. The reference implementations of SOAP from
developmentor [2] place thier accessors in the default
(null?) namespace which is where I first noticed this

Henry mentioned that there were compelling arguments
both for and against binding accessors to the parent
element namespace. I'm wondering if there should be an
RDF perspective on this issue?

Cordially from Corvallis,

Gabe Beged-Dov


[2] http://www.develop.com/soap

Received on Thursday, 6 January 2000 11:00:34 UTC

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