interface_polymorphism

Interface Polymorphism

    foreach $datum (@data) { $datum->print_me(); }

    @data = (
        XML::File->new("./lamasery.xml");
        HTTP::get->new("http://www.perl.org/news.html";);
        Signature->new();
    }

As long as each object's class's interface provides a print_me() method, the method call will handle $datum->print_me(); correctly. (Damian Conway, Object Oriented Perl, p. 204.)
In interface polymorphism, we're re-using the interface!