use v5.14;

package Person {
	use Moose;
	use overload q[""] => sub { $_[0]->name }, fallback => 1;
	
	has name => (
		is       => 'ro',
		isa      => 'Str',
		required => 1,
	);
}

package Club {
	use Moose;
	use overload q[""] => sub { $_[0]->name }, fallback => 1;

	has name => (
		is       => 'ro',
		isa      => 'Str',
		required => 1,
	);

	# This is a private attribute. We want people to only
	# manipulate the member list via add_members, etc.
	has _members => (
		traits   => ['Array'],
		is       => 'ro',
		isa      => 'ArrayRef[Person]',
		init_arg => undef,
		default  => sub { [] },
		handles  => {
			add_members   => 'push',
			has_members   => 'count',
			list_members  => 'elements',
			_uniq_members => 'uniq',
		},
	);
	
	# ensure uniqueness
	after add_members => sub {
		my $self = shift;
		@{ $self->_members } = $self->_uniq_members;
	};
}

my $club = Club->new(name => "The Breakfast Club");

$club->add_members(
	Person->new(name => "Allison"), 
	Person->new(name => "Andy"),
	Person->new(name => "Brian"),
	Person->new(name => "Brian"), # duplicate
);

$club->add_members(
	Person->new(name => "Andy"), # duplicate
	Person->new(name => "Claire"),
	Person->new(name => "John"),
);

say for $club->list_members;