2.4 XPath 1.0 Expressions

Arguments to some conditions, actions, and tokens use XPath 1.0 expressions. XPath is a language created to provide a common syntax and semantics for functionality shared between XSLT and XPointer. It is used primarily for addressing parts of an XML document, but also provides basic facilities for manipulation of strings, numbers and Booleans.

The XPath specification requires that the embedding application provide a context with several application-defined pieces of information. In DirXML Script (see Section 1.1.2, DirXML Script), XPath is evaluated with the following context:

Namespaces declarations to associate a prefix with a Java class must be declared on the policy element.

The W3 Web site contains further information.