#!perl
use strict;
use XML::Twig;

my $xml = q!<xml><test>
  <name> 111 </name><book> 234 </book>
</test><test>
  <name> 111 </name><book> abc </book>
</test></xml>!;

my $t = XML::Twig->new( 
  twig_handlers => {'test/book[string()=~/abc/]'=> \&book} 
);
$t->parse($xml);

sub book {
  my($t,$book) = @_;
  $book->parent->print;
  print "\n";
}