sub convert {
    my $re = shift;
    return bless \$re, __PACKAGE__;
}

use overload '""' => sub { ${ shift() } };
use overload '.' => \&concat;

sub concat {
    my($self, $str, $rev) = @_;
    my $string = $rev ? "$str" . "$self" : "$self" . "$str";
    return bless \$string, __PACKAGE__;
}