XSLT (The eXtensible Stylesheet Language: Transformations) is an XML application language used for transforming XML documents into other documents. It is implemented by an application called an XSLT processor that takes an XML document and an XSLT stylesheet as input and produces a new document by applying the instructions contained in the stylesheet to the original source XML document. The result of an XSLT transformation can be any text-based format, but the output is typically either another XML document, or a document in a widely deployed markup language such as HTML that can be readily consumed by a given client application.
AxKit is not an XSLT processor, nor does it ship with one. If you want to use XSLT to transform your XML content using AxKit, you need to install an XSLT processor and any necessary Perl interface modules separately. For the list of XSLT processors that AxKit currently supports, see XML Processing Options in Chapter 2. For details about how to use the AxAddStyleMap directive to associate XSLT stylesheets with the processor you install and the various directives that govern which stylesheets are applied to your XML documents, see Chapter 4.
Exhaustive coverage of XSLT is well beyond the scope of this chapter. The goal here is to introduce enough of the basic concepts of writing XSLT stylesheets to allow you to start being productive with AxKit as quickly as possible. For a more detailed look at XSLT, see XSLT , by Doug Tidwell, or Learning XSLT , by Mike Fitzgerald (both from O'Reilly). All of the samples here use only XSLT 1.0. At the time of this writing, XSLT 2.0 is still very new and not widely implemented, and existing implementations are highly experimental. Rest assured though, XSLT 1.0 is still a viable tool. The topics covered here generally apply to both versions, and support for use of Version 2.0 processors from within AxKit will be added just as soon as stable implementations begin to appear.