my $collection = Collection->new({ 'sorter' => Sort::mysorter });

$collection->doit;

package Collection;

sub new
{
  my ($class, $options) = @_;

  $self->{sorter} = \&{$options->{sorter}};
  bless {}, $class;
}

sub doit
{
    print "iam doit\n";
    $self->{sorter}->($mystuffToSort);
}

package Sort;

sub mysorter
{
    print "iam mysorter\n";
}