use XML::XPath;
use XML::XPath::XMLParser;

my $xp = XML::XPath->new(filename => './monk.xml');

my $nodeset = $xp->find('/monk[./vals/val[@val1 = "FOO"]]');

foreach my $node ($nodeset->get_nodelist) {
   my $say = $xp->findvalue('./say', $node);
   print "$say\n";
}