use strict;
use warnings;

use XML::Twig;
 
my $XML = "<errors>
  <error>
   <desc>First Error</desc>
  </error>
  <error>
    <desc>Second Error</desc>
  </error>
 </errors>";
 
sub print_error
{
  my ( $twig, $error ) = @_;
  print "NEW: ",$error -> first_child_text('desc'),"\n";
}

my $parser = XML::Twig -> new ( 'twig_handlers' => { 'error' => \&print_error } );
$parser -> parse ( $XML );