XSLT 1.0 Pocket Reference

Chapter 3. How XSLT Works

XSLT is a language for transforming XML documents. As described in Chapter 1, the XSLT processor is concerned with three XPath data model trees: the source tree, the stylesheet tree, and the result tree. Figure 3-1 shows the relationship between these three. The stylesheet and source trees are fed to the XSLT processor, which then produces the result tree.

Figure 3-1. The three trees present in every XSLT transformation

Stylesheet Structure

The general structure of an XSLT stylesheet looks like this:

<xsl:stylesheet version="1.0"
  xmlns:xsl="http://www.w3.org/1999/XSL/Transform">

  <!-- optional top-level elements, such as: -->
  <xsl:import href="..."/>
  <xsl:param name="..."/>

  <!-- set of template rules: -->
  <xsl:template match="...">...</xsl:template>
  <xsl:template match="...">...</xsl:template>
  ...

</xsl:stylesheet>

The document, or root, element of the stylesheet is xsl:stylesheet. Alternatively, you can use the xsl:transform element, which behaves exactly the same way. Which you use is a matter of personal preference. The XSLT namespace is http://www.w3.org/1999/XSL/Transform. The conventional namespace prefix is xsl, but any prefix can be used—provided that it binds to the XSLT namespace URI.

See Chapter 4 for a classification of all of XSLT’s elements and where they can occur within a stylesheet.

Processing Model

All XSLT processing consists of iterations over ...