Jonathan Borden released a new draft of the Resource Directory Description Language, providing one answer to the tricky question of what might live at the end of a namespace URI.

RDDL offers an answer to "what might a namespace URI mean?" by providing:

"a text description of some class of resources and of other resources related to that class. It also contains a directory of links to these related resources. An example of a class of resources is that defined by an XML Namespace. Examples of such related resources include schemas, stylesheets, and executable code. A Resource Directory Description is designed to be suitable for service as the body of a resource returned by deferencing a URI serving as an XML Namespace name."

RDDL is built using XLink and XHTML Basic, and adds a resource element with XLink attributes to XHTML Basic. The XHTML provides human-readable documentation, while the resource elements provide machine-readable connections to resources used for processing.

The RDDL documentation is itself a RDDL document, containing pointers to resources (DTDs, RELAX modules, an RDF Schema,OASIS Open Catalog, a CSS style sheet) within an XHTML Basic framework.

A Java API for RDDL processing is also under development. RDDL development takes place on the XML-Dev mailing list, with Jonathan Borden and Tim Bray serving as editors.

Related stories:

• Robin Cover's RDDL page (from The XML Cover Pages)
• The pot at the end of the namespace rainbow
• Old Ghosts: XML Namespaces (from XML.com)
• XML-URI activity proposal available for discussion
• W3C releases XML packaging information, starts mailing list