XML Hacks

Create an RDDL Document

RDDL is a XHTML language extension that can help dispel a confusion that surrounds XML namespaces, and let people find out more about your vocabularies.

The Resource Directory Description Language or RDDL (http://www.rddl.org) was developed by members of the xml-dev mailing list (http://www.xml.org/xml/xmldev.shtml) in late 2000 and early 2001; Jonathan Borden and Tim Bray were the primary developers. It was created as one possible solution to the XML namespace problem, which is basically that an URI that uses a http:// scheme suggests that the URI is pointing at a resource, such as an actual document; however, this is not necessarily the case with XML namespaces, and so it creates confusion.

RDDL provides a partial solution to this problem by providing a special document called a resource directory that can hold information about resources that are associated with a target namespace name. If you find XML namespaces a bit annoying, RDDL is a solution that can help. One of the main benefits of RDDL is that it’s both human- and machine-readable. It uses XHTML so you can read it in a browser, and it also use XLink, whose special natures and purposes can help an application discover other resources.

RDDL essentially extends the XHTML Basic module (http://www.w3.org/TR/xhtml-basic/) with a resource element. This element is allowed to contain mixed content [Hack #1] but chiefly it uses XML and XLink [Hack #28] attributes. Table 4-1 describes the attributes ...