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<s1 title="Extensions library">
<ul>
  <li><link anchor="intro">Introduction</link></li>
  <li><link anchor="exslt">Beta support for EXSLT extensions</link></li>
  <li><link anchor="xalanns">Xalan namespace</link></li>
  <li><link anchor="nodeset">nodeset</link></li>
  <li><link anchor="intersection">intersection</link></li>
  <li><link anchor="difference">difference</link></li>
  <li><link anchor="distinct">distinct</link></li>
  <li><link anchor="evaluate">evaluate</link></li>
  <li><link anchor="hassamenodes">hasSameNodes</link></li>
</ul>

<anchor name="intro"/>
<s2 title= "Introduction">
<p>Extension functions provide a powerful mechanism
   for extending and simplifying what you can do with an XLST processor like
   Xalan. With input and contributions from the XML open-source developer community, we are working on placing the most useful
   extensions in an extensions library distributed with &xslt4c;. If you have ideas and/or contributions you would like to make, 
   please email us at the <human-resource-ref idref="xalandev"/>.</p>
</s2>

<anchor name="exslt"/>
<s2 title="EXSLT extensions">
<p>&xslt4c; supports the <jump href="http://exslt.org/">EXSLT</jump> initiative to provide a set of
   standard extension functions to XSLT users. &xslt4c; includes beta implementations for 
   functions in four of the EXSLT namespaces (some are calls to extension already in the Xalan namespace).</p> 
<p>The source files for the implementations are in the XalanEXSLT subdirectory of the source tree.  See</p> 
<ul>
  <li><jump href="apiDocs/XalanEXSLTCommonImpl_8hpp.html">XalanEXSLTCommonImpl</jump></li>
  <li><jump href="apiDocs/XalanEXSLTMathImpl_8hpp.html">XalanEXSLTMathImpl</jump></li>
  <li><jump href="apiDocs/XalanEXSLTSetImpl_8hpp.html">XalanEXSLTSetImpl</jump></li>
  <li><jump href="apiDocs/XalanEXSLTStringImpl_8hpp.html">XalanEXSLTStringImpl</jump></li>
  <li><jump href="apiDocs/XalanEXSLTDynamicImpl_8hpp.html">XalanEXSLTDynamicImpl</jump></li>
  <li><jump href="apiDocs/XalanEXSLTDateTimeImpl_8hpp.html">XalanEXSLTDateTimeImpl</jump></li>
</ul>
<p>For the function specifications, see:</p>
<ul>
  <li><jump href="http://www.exslt.org/exsl/exsl.html">EXSLT common functions</jump></li>
  <li><jump href="http://www.exslt.org/math/math.html">EXSLT math functions</jump></li>
  <li><jump href="http://www.exslt.org/set/set.html">EXSLT set functions</jump></li>
  <li><jump href="http://www.exslt.org/str/str.html">EXSLT string functions</jump></li>
  <li><jump href="http://www.exslt.org/dyn/dyn.html">EXSLT dynamic functions</jump></li>
  <li><jump href="http://www.exslt.org/date/date.html">EXSLT date-time functions</jump></li>
</ul>
<p>Anyone who would like to participate in the &xslt4c; initiative to support EXSLT by testing these implementations or implementing 
   other EXSLT functions is more than welcome. Please email us at the <human-resource-ref idref="xalandev"/>.</p>
</s2>

<anchor name="xalanns"/>
<s2 title="Xalan namespace">
<p>We are placing the Xalan extension functions in the XalanExtensions module and we have defined a namespace for this module:</p>
<p>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<code>http://xml.apache.org/xalan</code></p>
<p>If you are calling &xslt4c;-supplied extensions, we recommend that you define this namespace in your stylesheet element, and 
   call the extension using the namespace prefix that you have associated with that namespace. That way, if we later reorganize 
   how the &xslt4c;-supplied extensions are stored, you won't have to modify your stylesheet.</p>
<p>For an example that uses this namespace, see <link anchor="ex-nodeset">Example with the nodeset extension function</link>.</p>
</s2>

<anchor name="nodeset"/>
<s2 title= "nodeset">
<p>Implemented in <jump href="apiDocs/classFunctionNodeSet.html">FunctionNodeSet</jump>, <code>nodeset (result-tree-fragment)</code> 
   casts a result tree fragment into a node-set.</p>
<note>When you bind a variable to a template, rather than to the value generated by a select expression, the data type of the variable 
      is result tree fragment. For more information, see <jump href="http://www.w3.org/TR/xslt#section-Result-Tree-Fragments">Result 
      Tree Fragments</jump>.</note>

<anchor name="ex-nodeset"/>
<s3 title="Example with the nodeset extension function">
<p>The following stylesheet uses the nodeset extension function to cast a result tree fragment into a node-set that can then be 
   navigated in standard XPath manner. It uses the http://xml.apache.org/xalan namespace to provide access to the nodeset() method 
   in xml.apache.xalan.lib.Extensions.</p>
<source>
&lt;?xml version="1.0"?&gt;
&lt;xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" 
                   version="1.0"
                   xmlns:xalan="http://xml.apache.org/xalan"
                   exclude-result-prefixes="xalan"&gt;
&lt;xsl:template match="/"&gt;
  &lt;out&gt;
	  &lt;xsl:variable name="rtf"&gt;
      &lt;docelem&gt;
        &lt;elem1&gt;
          &lt;elem1a&gt;ELEMENT1A&lt;/elem1a&gt;
          &lt;elem1b&gt;,ELEMENT1B&lt;/elem1b&gt;
        &lt;/elem1&gt;
        &lt;elem2&gt;
          &lt;elem2a&gt;ELEMENT2A&lt;/elem2a&gt;
        &lt;/elem2&gt;
      &lt;/docelem&gt;
    &lt;/xsl:variable&gt;     
      &lt;xsl:for-each select="xalan:nodeset($rtf)/docelem//*"&gt;
        &lt;xsl:value-of select="name(.)"/&gt;&lt;xsl:text&gt;,&lt;/xsl:text&gt;
      &lt;/xsl:for-each>
  &lt;/out>
&lt;/xsl:template> 
&lt;/xsl:stylesheet&gt;
</source>
<p>The output of running this stylesheet (with any XML input source) is a comma-delimited list of the element names in the node-set<br/>
   &nbsp;&nbsp;<code>&lt;out&gt;elem1,elem1a,elem1b,elem2,elem2a&lt;/out&gt;</code></p>
<note>For illustration purposes, the preceding stylesheet pays no attention to the structure and content of the XML input document. 
      Instead, it processes the template (in the stylesheet) bound to the variable named rtf.</note>
</s3>
</s2>
<anchor name="intersection"/>
<s2 title="intersection">
<p>Implemented in <jump href="apiDocs/classFunctionIntersection.html">FunctionIntersection</jump>, <code>intersection (node-set1, 
   node-set2)</code> returns a node-set with all nodes that are in ns1 and in ns2.</p>
</s2>
<anchor name="difference"/>
<s2 title= "difference">
<p>Implemented in <jump href="apiDocs/classFunctionDifference.html">FunctionDifference</jump>, <code>difference(node-set1, 
   node-set2)</code> returns a node-set with the nodes in node-set1 and not in node-set2.</p>
</s2>
<anchor name="distinct"/>
<s2 title= "distinct">
<p>Implemented in <jump href="apiDocs/classFunctionDistinct.html">FunctionDistinct</jump>, distinct (node-set) returns a node-set 
   containing nodes with distinct string values. If more than one node in the node-set contains the same text node value, distinct 
   only returns the first of these nodes that it finds.</p>
</s2>
<anchor name="evaluate"/>
<s2 title= "evaluate">
<p>Implemented in <jump href="apiDocs/classFunctionEvaluate.html">FunctionEvaluate</jump>, <code>evaluate (xpath-expression)</code> 
   returns the result of evaluating the xpath-expression in the current XPath expression context (automatically passed in by the 
   extension mechanism).</p>
<p>Use the evaluation extension function when the value of the expression is not known until run time.</p>
</s2>
<anchor name="hassamenodes"/>
<s2 title= "hasSameNodes">
<p>Implemented in <jump href="apiDocs/classFunctionHasSameNodes.html">FunctionHasSameNodes</jump>, <code>hasSameNodes(node-set1, 
   node-set2)</code> returns true if both node-set1 and node-set2 contain exactly the same set of nodes.</p>
</s2>
</s1>
