SAMS Teach Yourself Perl in 24 Hours THIRD EDITION

XML Data

Hierarchical data comes in many forms. As noted before, the index and table of contents of this book are largely hierarchical. Many methods of representing this kind of data structure have been developed over the years. The most common one in use now is called eXtensible Markup Language or XML.

XML is a format developed by the World Wide Web Consortium (W3C). It consists of a text document. Inside of that document are a series of elements, nested within each other. There is one element that encompasses the entire document called the root element. Each element is enclosed in a pair of tags—empty elements can be represented by a single start-and-end tag. Elements can have attributes, which are indicated in the opening tag. A sample XML ...