Inheritance

Class definitions

Parent class:

package Dinosaur;
use Moo;

has eyes            => (is => 'ro', default => sub { 2 });
has big_sharp_teeth => (is => 'ro', default => sub { 120 });

1;

Child class:

package Stegosaurus;
use Moo;
extends 'Dinosaur';

has tail_with_spikes => (is => 'ro', default => sub { 1 });

# override the default from the parent
has '+big_sharp_teeth' => (default => sub { 0 });

1;

Resulting object

use Stegosaurus;
my $steg = Stegosaurus->new();
$steg->eyes;              # has 2 eyes
$steg->tail_with_spikes;  # has a tail with spikes
$steg->big_sharp_teeth;   # has 0 big sharp teeth