Please note that XML::LibXSLT, the XSLT companion to XML::LibXML offers the "register_function" functionality which allows Perl functions to be called from stylesheets. An example (directly from the XML::LibXSLT documentation):

 XML::LibXSLT->register_function("urn:foo", "bar", sub { scalar localt
+ime });
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<xsl:stylesheet version="1.0"
    xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
    xmlns:foo="urn:foo">
  <xsl:template match="/">
    The time is: <xsl:value-of select="foo:bar()"/>
  </xsl:template>
  </xsl:stylesheet>
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This implies that CPAN modules can be made available at least in stylesheets using XML::LibXSLT.

I've used this approach for a client, who is now running about 40 syndicated websites out of a single database in production using this approach. Even the associated CMS is using XML::LibXSLT with special custom functions for handling forms and updating the underlying database.

Typical modules that I've made available that way (directly or indirectly) are DBI, LWP::UserAgent, POSIX, Digest::MD5, Email::Valid, Time::ParseDate, etc. etc. etc.

Liz