XML::LibXSLT

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parse_stylesheet($stylesheet_doc)

$stylesheet_doc here is an XML::LibXML::Document object (see XML::LibXML) representing an XSLT file. This method will return a XML::LibXSLT::Stylesheet object, or undef on failure. If the XSLT is invalid, an exception will be thrown, so wrap the call to parse_stylesheet in an eval{} block to trap this.

IMPORTANT: $stylesheet_doc should not contain CDATA sections, otherwise libxslt may misbehave. The best way to assure this is to load the stylesheet with no_cdata flag, e.g.
my $stylesheet_doc = XML::LibXML->load_xml(location=>"some.xsl", no_cdata=>1);