An Introduction to XML Applications

In this chapter we’ll be looking at some examples of XML
applications, markup languages used to further refine XML,
and behind-the-scene uses of XML. It is inspiring to look at
some of the uses to which XML has already been put, even in
this early stage of its development. This chapter will give you
some idea of the wide applicability of XML. Many more XML
applications are being created or ported from other formats
as I write this.
Part V covers some of the XML applications discussed in
this chapter in more detail.
What Is an XML Application?
XML is a meta-markup language for designing domain-specific
markup languages. Each XML-based markup language is called
an XML application. This is not an application that uses XML
like the Mozilla Web browser, the Gnumeric spreadsheet, or
the XML Pro editor, but rather an application of XML to a
specific domain such as Chemical Markup Language (CML) for
chemistry or GedML for genealogy.
Each XML application has its own syntax and vocabulary. This
syntax and vocabulary adheres to the fundamental rules of
XML. This is much like human languages, which each have
their own vocabulary and grammar, while at the same time
adhering to certain fundamental rules imposed by human
anatomy and the structure of the brain.