# Script part 2.
{   package StringRef;
    use overload '""' => sub {
        shift->{STRING};
    };
}


{   package StringRefHash;
    use Tie::Hash;
    our @ISA = 'Tie::StdHash';

    sub STORE {
        my ($self, $key, $value) = @_;
        $self->{$key} = bless {STRING => $value}, 'StringRef';
    }
}


tie my %list, 'StringRefHash';
eval $code;