My action on namespaces

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Here is my much belated draft of some text on namespaces[1] for the
architecture document.

XML vocabularies use URIs, as per Namespaces in XML, as "namespace
names" to create globally unique element and attribute names. These
URIs are identified in an XML document with a namespace declaration.

Although the Namespaces Recommendation makes it clear that it is not
<em>necessary</em> for the namespace name to be a retrievable
resource, the "resource description" principle suggests that it
<em>should</em> be a retrievable resource.

Presented with a namespace name that it does not recognize, the URI is
the only key that a person or application has to find out more about
the namespace. The natural way to find out more about a resource
identified by a URI is to dereference it.

There are many reasons why a person or agent might want more
information about the namespace. A person might want to

 * understand its purpose,
 * find out who controls it,
 * request authority to access it, or
 * report a bug or situation that could be considered an error

An agent might undertake to retreive that information for a user,
or it might be searching for other kinds of information, such as:

 * a schema to use for validation
 * a stylesheet to use for presentation
 * an ontology to use for making inferences, or
 * any number of other application-specific details

It follows that there is, in general, no single type of resource that
can be returned in response to a request for the namespace name that
will always be the most appropriate.

Consequently, it often makes sense to use some sort of hybrid document
that indirectly provides access to a variety of resources as the
document available from the namespace name. One example of such a
hybrid document is RDDL.

Note, however, that RDDL or a document like it, is no more universally
correct than any other type of resource. For any particular namespace,
there might be a single best answer (schema, ontology, HTML
documentation, etc.), as determined by the developers of that

                                        Be seeing you,


- -- 
Norman.Walsh@Sun.COM    | The Future is something which everyone
XML Standards Architect | reaches at the rate of sixty minutes an hour,
Web Tech. and Standards | whatever he does, whoever he is.--C. S. Lewis
Sun Microsystems, Inc.  | 
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Received on Monday, 11 November 2002 10:51:58 UTC