Chapter 20. Expressions

Earlier chapters have introduced the expression language used in the XSLT standard to trigger and configure templates, locate and reuse information, define keys, and for other purposes. Mostly, these expressions are defined in a separate standard called XPath; though XSLT adds some functions and defines a subset of XPath for use in special circumstances. This chapter provides a thorough examination of the XPath standard and the XSLT enhancements.