#!perl
use strict;
use XML::Twig;
my $xml = do { local $/; <DATA> };
my $twig = new XML::Twig(
    twig_handlers =>{ li => \&li},
);
$twig->parse($xml);

sub li {
  my ($t,$elt) = @_;
  print $elt->text;
  if ( $elt->parent('p[@conref != ""]') ){
    print " yes\n";
  } else {
    print " no\n";
  }
}

__DATA__
<xml>
<p conref="hello">
 <ul>
  <li>Bob</li>
  <li>Mary</li>
 </ul>
</p>
<p conref="">
 <ul>
  <li>Tom</li>
  <li>Susan</li>
 </ul>
</p>
</xml>