#!/usr/bin/perl -w
{
	package NumberObject;
	use overload '""' => \&as_string, '0+' => \&as_number, '+' => \&add;

	sub new {
    	my $class = shift;
        my $value = shift;
        bless \$value, $class;
    }

    sub as_string {
    	return "" . ${+shift};
    }
    sub as_number {
    	return 0 + ${+shift};
    }

    sub add {
    	my $self = shift;
        return ref($self)->new($self->as_number + shift);
    }

    sub inc {
    	my $self = shift;
        $$self += shift;
	}
}

$\ = "\n";
my $printnumber = new NumberObject(-1);
print "initial value:";
print $printnumber;
print "looping:";
for (1 .. 10) {
	inc $printnumber 1;
    print $printnumber;
}

print "overload magic (adding 5):";
$printnumber += 5;
print $printnumber;
print "still an object (adding 2):";
inc $printnumber 2;
print $printnumber;