I don't understand UNIVERSAL::DOES()

[rlb3]

Hello,

I've been toying around with perl 5.9.4. Just testing out some of the new features. One of those feature I don't understand is UNIVERSAL::DOES(). I've read the perldelta for perl 5.9.4 and the newest edition of The Perl Review which a has an article on perl 5.9.4, but I'm still not getting it. I don't see how it is difference from ISA. Here is some test code I wrote.

#!/opt/bleadperl/bin/bleadperl

package Role;

package Object;
@Object::ISA= ('Role');

sub new {
    my $class = shift;

    return bless {}, $class;

}

package main;

my $o = Object->new();

print 'Object DOES Role' if $o->DOES(Role);

I don't see how this is really different than using ->isa(). I understand how roles work in Class::Traits and Moose, but I don't have to use @ISA to setup the relationship. I think i'm missing soming basic or I really don't understand how roles or traits are supposed to work. Can someone point me in the right direction?

Thanks,