For eg. Here is a snippet from game.t test from MooseX::MultiMethods on GitHub @ http://github.com/rafl/moosex-multimethods/tree/master

{
    package Paper;    use Moose;
    package Scissors; use Moose;
    package Rock;     use Moose;
    package Lizard;   use Moose;
    package Spock;    use Moose;

    package Game;
    use Moose;
    use MooseX::MultiMethods;

    multi method play (Paper    $x, Rock     $y) { 1 }
    multi method play (Paper    $x, Spock    $y) { 1 }
    multi method play (Scissors $x, Paper    $y) { 1 }
    multi method play (Scissors $x, Lizard   $y) { 1 }
    multi method play (Rock     $x, Scissors $y) { 1 }
    multi method play (Rock     $x, Lizard   $y) { 1 }
    multi method play (Lizard   $x, Paper    $y) { 1 }
    multi method play (Lizard   $x, Spock    $y) { 1 }
    multi method play (Spock    $x, Rock     $y) { 1 }
    multi method play (Spock    $x, Scissors $y) { 1 }
    multi method play (Any      $x, Any      $y) { 0 }
}

my $game = Game->new;
ok($game->play(Spock->new, Scissors->new), 'Spock smashes Scissors');
ok(!$game->play(Lizard->new, Rock->new), 'Rock crushes Lizard');
ok(!$game->play(Spock->new, Paper->new), 'Paper disproves Spock');

/I3az/

The example doesn’t go into the powerful method signatures you get with MooseX::Declare and there’s already code out there for multi methods and return signatures. There’s planned enhances nearly CPAN ready for even more advanced type constraints and talk about Lisp style conditions.

After that there’s going to be tons of new stuff in big projects like Catalyst and related, which has just recently become Moose based.