RegExp in XSLT

<doc>
  <members>
    <member name="F:MyNamespace">
      <summary>Some text</summary>
    </member>
  </members>
</doc>

<?xml version="1.0" encoding="utf-8"?>
<xsl:stylesheet
version="1.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
xmlns:fn="http://www.w3.org/TR/xpath-functions/"
>
    <xsl:template match="/" >
    	<html xmlns="http://www.w3.org/1999/xhtml">
    		<body style="font-family:Tahoma">
    		<p>Interfaces list:</p>
    			<table>
    				<xsl:for-each select="doc/members/member">
    					<xsl:sort order="ascending" />
    					<xsl:value-of select="fn:matches(., 'P..+')" />
    					<br />
    				</xsl:for-each>
    			</table>
    		</body>
    </html>
</xsl:template>
</xsl:stylesheet>