XML::Compile::Schema, https://metacpan.org/source/PERIGRIN/XML-Toolkit-0.15/ex/aiml/XML/AIML/Aiml.pm

#!/usr/bin/perl --
use strict; use warnings;
use XML::LibXML 1.70; ## for load_html/load_xml/location
use XML::Compile::Schema;
our $AIML_URL   = 'http://files.aitools.org/programd/resources/schema/
+AIML.xsd';
my $adom = XML::LibXML->new(qw/ recover 2 /)->load_xml( location => $A
+IML_URL   ); ## no caching
my $aiml = XML::Compile::Schema->new( $adom);
$aiml->printIndex;
## print "\n$adom\n";
print $adom->find(q{  //*[ @name="OneOrTwoDIndexedElement"] } )->get_n
+ode(0), "\n";
[download]

... xpather.pl