Hello wise Monks!

I am studying Perl OO programming and I have learned how to create classes using modules as packages saved in .pm files. I was wondering whether it is possible to do all that in a single file, so that distributing a perl script would be easier.

I have started experimenting with defining multiple packages in a single script and I seem to be able to create classes and new objects, but so far I had no success trying to implement inheritance.

With the following code I am trying to define two classes: Class1, which is the parent, and Class2 which should inherit from Class1. I was hoping it would work, but actually it doesn't and my Class2 is not a child of Class1 (it cannot find the method PrintHello).

Is this just impossible within a single file or am I missing something?

#!/usr/bin/perl
use warnings;
use strict;
use Data::Dumper;

my $max = Class2->new(NAME => 'MaxKlokan') ;
$max->PrintHello();
print Dumper $max;

exit;

#######################
{
    package Class1;
    
    sub new {
        my $classname  = shift;
        my $self       = {@_};
        $self->{NAME}   = undef unless $self->{NAME};
        $self->{AGE}    = undef unless $self->{AGE};
        bless($self,$classname);
        return $self;
    }

    sub PrintHello
    {
        my $this = shift;
        print "Hello $this->{NAME}\n";;
    }
}

#######################
{
    package Class2;
    require Class1;

    @Class2::ISA = qw(Class1);

    sub new {
        my $classname  = shift;
        my $self       = Class1->new();
        $self->{TITLE}  = undef  unless $self->{TITLE};
        bless($self,$classname);
        return $self;
    }
}
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