Re: Moose(X) create my own Collection

[tobyink]

You don't want to define MyCollection as a class. Define it as a parameterised role instead. IIRC, there is some MooseX::Declare syntactic sugar for parameterised roles, but I can't remember exactly how it goes, and it's undocumented.

package MyCollection;
use MooseX::Role::Parameterized;

parameter type => (
  isa      => 'ClassName',
  required => 1,
);

parameter attr => (
  isa      => 'Str',
  required => 1,
);

role {
  my $p = shift;
  my ($type, $attr) = ($p->type, $p->attr);

  has $attr => (
    is => 'rw',
    isa => "HashRef[$type]",
    traits => ['Hash'],
    defaults => sub { {} }
    );

  method "summon_$attr" => sub {
    my $self = shift;
    foreach my $item (values %{ $self->$attr }) {
      $item->summon if $item->does('Summonable');
    }
  };
};

# and we'll use MooseX::Declare syntax for the rest...

role Summonable {
  requires 'name';
  method summon {
    say "Come here, ", $self->name;
  }
}

class Child with Summonable {
  has name => ( is => 'ro', isa => 'Str' );
}

class Parent {
  with MyCollection => { type => 'Child', attr => 'children' };
}

my $me = Parent->new;
$me->children->{isabel} = Child->new(name => 'Isabel');
$me->children->{elliott} = Child->new(name => 'Elliott');
$me->summon_children;

The above is untested, and probably has some syntax errors lurking somewhere, but it should give you an idea of how it can be done.