My wife's been chasing grasshoppers this fall:
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Sometimes it's useful to detect which XSLT engine your XSLT stylersheet is being executed by, e.g. to shortcut processing using an engine-specific extension function or to workaround a bug in particlular engine. Now that Microsoft alone ships 3 different XSLT engines - MSXML3/MSXML4/MSXML5/MSXML6, XslTransform and XslCompiledTransform, detecting XSLT engine from
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MSXML supports "ms:version" system property, which can be retrieved using standard XSLT system-property() function. The value returned is MSXML version - "3", "4", "5" and so on. XslTransform doesn't support "ms:version" property and returns empty string (just like any other non-Microsoft XSLT engine). But new XslCompiledTransform does support it and "returns a string representing the version of the assembly implementing XslCompiledTransform in the same format as returned by Assembly.ImageRuntimeVersion property ('v2.0.50727' for .NET Framework 2.0)."
This, along with standard 'xsl:vendor' property should give us enough information to differentiate between Microsoft XSLT engines. Here is a sample XSLT stylesheet that does the trick:
<![CDATA[<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
xmlns:ms="urn:schemas-microsoft-com:xslt" exclude-result-prefixes="ms">
<xsl:template match="/">
<p>
This XSLT stylesheet is being executed using
<xsl:choose>
<xsl:when test="system-property('xsl:vendor') = 'Microsoft'">
<xsl:text>Microsoft </xsl:text>
<xsl:variable name="ms-version" select="system-property('ms:version')"/>
<xsl:choose>
<xsl:when test="$ms-version = ''">XslTransform</xsl:when>
<xsl:when test="starts-with($ms-version, 'v')">XslCompiledTransform</xsl:when>
<xsl:otherwise>
MSXML
<xsl:value-of select="$ms-version" />
</xsl:otherwise>
</xsl:choose>
</xsl:when>
<xsl:otherwise>
Unrecognized XSLT engine from
'<xsl:value-of select="system-property('xsl:vendor')" />'
</xsl:otherwise>
</xsl:choose>
</p>
</xsl:template>
</xsl:stylesheet>]]>