Enables the ability to use PHP functions as XSLT functions

Description

public XSLTProcessor::registerPHPFunctions(array|string|null $functions = null): void

This method enables the ability to use PHP functions as XSLT functions within XSL stylesheets.

Parameters

functions

Use this parameter to only allow certain functions to be called from XSLT.

This parameter can be one of the following: a string (a function name), an indexed array of function names, or an associative array with keys being the function name and the associated value being the callable.

Errors/Exceptions

Throws a ValueError if a callback name is not valid.
Throws a ValueError if options contains an invalid option.
Throws a ValueError if overrideEncoding is an unknown encoding.
Throws a TypeError if a given callback is not callable.

Return Values

No value is returned.

Changelog

Version	Description
8.4.0	Invalid callback names now throws a ValueError. Passing a non-callable entry now throws a TypeError.
8.4.0	It is now possible to use callables for callbacks when using `functions` with array entries.

Examples

Example #1 Simple PHP Function call from a stylesheet

<?php
$xml = <<<EOB
<allusers>
 <user>
  <uid>bob</uid>
 </user>
 <user>
  <uid>joe</uid>
 </user>
</allusers>
EOB;
$xsl = <<<EOB
<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet version="1.0" 
     xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
     xmlns:php="http://php.net/xsl">
<xsl:output method="html" encoding="utf-8" indent="yes"/>
 <xsl:template match="allusers">
  <html><body>
    <h2>Users</h2>
    <table>
    <xsl:for-each select="user">
      <tr><td>
        <xsl:value-of
             select="php:function('ucfirst',string(uid))"/>
      </td></tr>
    </xsl:for-each>
    </table>
  </body></html>
 </xsl:template>
</xsl:stylesheet>
EOB;
$xmldoc = new DOMDocument();
$xmldoc->loadXML($xml);
$xsldoc = new DOMDocument();
$xsldoc->loadXML($xsl);

$proc = new XSLTProcessor();
$proc->registerPHPFunctions();
$proc->importStyleSheet($xsldoc);
echo $proc->transformToXML($xmldoc);
?>

XSLTProcessor::registerPHPFunctions