use strict;
use warnings;
use MooseX::Struct;

immutable struct Cat => (
	name => { isa => 'Str' },
);

immutable struct Litter => (
	cats => { isa => 'ArrayRef[Cat]' },
);

my $cat1   = Cat->new(name=>'Garfield');
my $cat2   = Cat->new(name=>'Felix');
my $litter = Litter->new(cats => [$cat1, $cat2, 1]);