package Wibble;
use Moose;
use MooseX::AttributeHelpers;

has 'thingies' => (
  metaclass => 'Collection::Array',
  is        => 'ro',
  isa       => 'ArrayRef[Str]',
  default   => sub { [] },
  provides  => {
      push     => 'add_thingies',
      elements => 'list_thingies',
  },
);

##</code><code>##

my $w = Wibble->new( thingies => [ 'this', 'that' ]);

print join(", ",$w->list_thingies())."\n";
# prints "this, that"

# here's the bit that we just made work
$w->add_thingies('another');

print join(", ",$w->list_thingies())."\n";
# prints "this, that, another"