Perl as a career option(linuxcareer.com)

    use Moops;

    role NamedThing {
       has name => (is => "ro", isa => Str);
    }

    class Person with NamedThing;

    class Company with NamedThing;

    class Employee extends Person {
       has job_title => (is => "rwp", isa => Str);
       has employer  => (is => "rwp", isa => InstanceOf["Company"]);

       method change_job ( Object $employer, Str $title ) {
          $self->_set_job_title($title);
          $self->_set_employer($employer);
       }

       method promote ( Str $title ) {
          $self->_set_job_title($title);
       }
    }