\chapter{Structured Markup Processing Tools \label{markup}} Python supports a variety of modules to work with various forms of structured data markup. This includes modules to work with the Standard Generalized Markup Language (SGML) and the Hypertext Markup Language (HTML), and several interfaces for working with the Extensible Markup Language (XML). It is important to note that modules in the \module{xml} package require that there be at least one SAX-compliant XML parser available. Python includes an interface to the Expat parser as the \refmodule{xml.parsers.expat} module, but this may not be built by default on all platforms, since Expat is not always installed, or not installed in the default location for libraries. If this is the case for your system, the easiest way to add support for the \module{xml} package is to install the \ulink{PyXML add-on package}{http://pyxml.sourceforge.net/}. That package provides an extended set of XML libraries for Python. The documentation for the \module{xml.dom} and \module{xml.sax} packages are the definition of the Python bindings for the DOM and SAX interfaces. \localmoduletable \begin{seealso} \seetitle[http://pyxml.sourceforge.net/] {Python/XML Libraries} {Home page for the PyXML package, containing an extension of \module{xml} package bundled with Python.} \end{seealso}