Something like:

use strict;
use warnings;
use XML::Twig;

my $xml = <<XML;
<root>
    <tag1>
        tag 1 data
    </tag1>
    <tag2>  
        tag 2 data
    </tag2>
</root>
XML

my $root = XML::Twig->new (
    twig_handlers => 
        {
        tag1 => \&process1,
        tag2 => \&process2,
        }
    );

$root->parse ($xml);


sub process1 {
    print "Process1: " . $_->children_text () . "\n";
}


sub process2 {
    print "Process2: " . $_->children_text () . "\n";
}
[download]

Prints:

Process1: 
        tag 1 data
    
Process2:   
        tag 2 data
[download]