In this chapter, we have learned how to use several PEAR packages that can be used when working with XML. XML_Util, XML_FastCreate, and XML_Serializer can be used to easily create generic XML documents without having to worry about the rules of well-formed XML documents or tag indentation. XML_XUL allows us to create applications for Mozilla-based browsers like Firefox using PHP. This allows us to share the business logic with standard web applications but exchange the front end of our applications with an XUL-based interface.
In the second half of the chapter we have learned how to build a SAX-based parser to read an XML-based configuration file and automatically ignore the parts of the XML document that are not important to us. We have used XML_Unserializer to create arrays and objects from virtually any XML document. This allows us easy access to information stored in an XML document without needing to know anything about the parsing process itself. Last, we used the XML_RSS package...