There are many good texts on XML, but in a nutshell it represents a markup language which allows information to be structured and shared between different systems. It comes from the HTML and SGML markup languages and is really a subset of those that do not have the specific goals of page layout. Here is a simple example of an XML Document:

<?xml version="1.0?">

<Chart>

   <ChartTitle>

      <Attribute name="Title">Line Chart</Attribute>

      <Attribute name="FontSize" value="14"/>

      <Attribute name="FontStyle" value="3"/>

   </ChartTitle>

</Chart> 

The XML document contains a prolog which defines some basic version information, and a number of tags or “nodes” which themselves can specify content (for example: “Line Chart”) or attribute information (for example: name=“title”). The nodes can be arranged in a hierarchical tree to indicate associations and groupings.

XML is finding uses in many different applications, but a primary use is the exchange of information between different applications or processes. Because it is text based it allows information to be exchanged between different platforms and easily moved over the web. Because there are XML parsers available in many languages it is easy to write application that can create and access XML data.

The XML parser used in the PV‑WAVE XML Toolkit is based on the libxml library (http://xmlsoft.org). You can receive XML data in PV‑WAVE from files, sockets, RPC’s, via JWAVE, or other sources. The XML documents can be parsed, searched, modified, and written back out to files or directly to other applications using sockets, etc. You can even create XML Documents from scratch using the toolkit. PV‑WAVE can be easily integrated with other applications that use XML as an information interchange mechanism.