package MyParent::MyChild;
use strict;
no strict "refs";
use Carp qw(carp croak);
use parent qw(MyParent);

our @ISA = qw(MyParent);

our @EXPORT = qw( method_a method_b );

my $VERSION = .01;

sub new {
    my $class = shift;
    my $this = bless {}, $class;
    my( $parent ) = @_;
    $this->{PARENT} = $parent;
    return $this;
}

sub child_method_a {
   #read parent variable, not change it
   print MyParent->{something};
}

sub child_method_b {
   ... incredibly cool stuff ...
}