Nope. Rules is a stream parser with a twist, but is in no way related to SAX (Simple API for XML) standard and XML::Twig is a tree based parser with a twist with no relation to the DOM standard. Both sit on top of XML::Parser (actually, XML::Parser::Expat in case of XML::Rules, but that's part of the package). There are several Perl implementations of both SAX and DOM and several modules that have their own different (usually more perlish) API.