Point_classic_moose.pl

{  
    package Point;  
    use Moose;  
  
    has x => ( isa => 'Int', is => 'rw' );  
    has y => ( isa => 'Int', is => 'rw' );  
  
    sub negated {  
        my $self = shift;  
        $self->new( x => -$self->x, y => -$self->y );  
    }  
  
    sub transpose {  
        my $self = shift;  
        $self->new( x => $self->y, y => $self->x );  
    }  
  
    sub inspect { say "$_[0]->{x} \@ $_[0]->{y}" }  
  
    no Moose;  
}  
  
my $p = Point->new( x => 4, y => 3 );  
  
$p->negated->inspect;     # => -4 @ -3  
$p->transpose->inspect;   # => 3 @ 4  

{  
    package Negated;  
    use Moose::Role;  
  
    requires 'transpose';  
  
    sub negated {  
        my $self = shift;  
        $self->transpose;  
    }  
  
    no Moose::Role;  
}  

Negated->meta->apply( $p );  
$p->negated->inspect;     # => 3 @ 4  
$p->transpose->inspect;   # => 3 @ 4