Re^3: I don't understand why I'm getting an "Use of uninitialized value" error

Exactly that is demonstrated in the example for the section Processing just parts of an XML document. One way of achieving that is:

#!/usr/bin/perl -w
use warnings;
use strict;
use XML::Twig;

my $xml = <<XML;
<head><ID>This is an id</ID>
    <Book1>
    <Title>
    Title stuff
    </Title>
    </Book1>
    <Book2><Title>Another title</Title></Book2>
</head>
XML

my $twig = XML::Twig->new(
    twig_roots => {
        ID          => \&dump,
        TimeStamp   => \&dump,
        IP_Address  => \&dump,
        'Book1/Title'       => sub {title (1, @_);},
        'Book2/Title'       => sub {title (2, @_);},
        Complainant => \&dump,
        }
        );

$twig->parse($xml);


sub dump {
    my ($t, $elt) = @_;
    (my $text = $elt->text()) =~ s/^\s+|\s+$//g;

    print "$text\n";
}


sub title {
    my ($type, $t, $elt) = @_;
    (my $title = $elt->text()) =~ s/^\s+|\s+$//g;
    
    print "Title $type: $title\n";
}
[download]

Prints:

This is an id
Title 1: Title stuff
Title 2: Another title
[download]

Take this code. Make sure you have XML::Twig installed. Play with it until you have some understanding of how it works.

True laziness is hard work

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