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Xalan-C++ Overview
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Xalan-C++ Overview



Xalan-C++ (named after a rare musical instrument) implements the W3C Recommendation 16 November 1999 XSL Transformations (XSLT) Version 1.0 and the XML Path Language (XPath) Version 1.0. XSLT is the first part of the XSL stylesheet language for XML. It includes the XSL Transformation vocabulary and XPath, a language for addressing parts of XML documents. For links to background materials, discussion groups, frequently asked questions, and tutorials on XSLT, see Getting up to speed with XSLT.

note XSL also includes a vocabulary for formatting documents, which is not part of Xalan-C++. For more information, see Extensible Stylesheet Language (XSL) Version 1.0 W3C Recommendation and the Apache XML FOP (Formatting Objects Project) .

You use the XSLT language to compose XSL stylesheets. An XSL stylesheet contains instructions for transforming XML documents from one document type to another document type (XML, HTML, or other). In structural terms, an XSL stylesheet specifies the transformation of one tree of nodes (the XML input) into another tree of nodes (the output or transformation result).

note The XSL stylesheet may generate and refer to cascading style sheets (CSS) as part of its output.

In the following example, the foo.xsl stylesheet is used to transform foo.xml into foo.out:


<?xml version="1.0"?>


<?xml version="1.0"?> 
<xsl:stylesheet xmlns:xsl="" version="1.0">
<xsl:template match="doc">
<out><xsl:value-of select="."/></out>




Xalan-C++ Features


Getting to work with Xalan-C++

For instructions and some suggestions about how to get started using Xalan-C++, see Downloading Xalan-C++, Building Xalan-C++, and Installing Xalan-C++.


Getting up to speed with XSLT

If you are still working through the details of the XSLT spec (the W3C 1.0 Recommendation), you may want to consult one or more of the following:

When you come across other useful introductory or background materials, please email Xalan Development Mailing List, so we can add them to this list.



XSLT Namespace

The XML namespace for XSLT. An XML namespace is a collection of element and attribute names, identified by a Unique Resource Identifier (URI), which often takes the form of a URL, but is really just a unique string, not a pointer to a web page. The XSLT namespace URI is In each XSLT stylesheet, you must declare this namespace in the stylesheet element tag and bind it to a local prefix. Like the XSLT specification, we always use xsl as the XSLT namespace prefix in our descriptions and examples, although you are free to bind any prefix to this namespace.

XSL Instruction

Any tag associated with the XSLT namespace.


An element, usually with child elements, that specifies a "rule" or set of instructions to perform when a particular kind of node is encountered in the source tree.

XSL Template Instruction

Any tag that occurs inside an xsl:template element and is associated with the XSLT namespace.

Source Tree

The XML tree input to the XSL process.

Result Tree

The tree that is output by the XSL process.

Match Pattern

The part of a template that defines the kind(s) of nodes to which the template applies.

For more definitions of XSLT terminology, see Dave Pawson's XSLT Terminology Clarification and the Glossary in Michael Kay's XSLT Programmer's Reference.