I'm not too familiar with overloading, so this is a "wonder if I can get that to work" snippet instead of a "I'd recommend doing it this way" suggestion.

Perhaps someone more familiar with overloading can point out the shortcomings of this quick hack. (other than not working for negative numbers, and the really poor algorithm of repeating $x++ 10 times for $x + 10)

#!/usr/bin/perl -wT
use strict;

package MagicalPlus;

use overload
        '""'       => sub { ${$_[0]} },
        '+'        => \&myadd,
        'fallback' => 1;

sub myadd {
  my $first = ${$_[0]};
  my $second = $_[1];
  $first++ while($second-->0);
  return addmagic($first);
}

sub addmagic {
        my $string = "".shift;
        my $self = \$string;
        bless($self, __PACKAGE__);
}

package main;

my $x = MagicalPlus::addmagic "006";      # create our magic var

for (1..10) {                             # watch it works its magic
  print "$x + $_ = ";
  $x = $x + $_;        # magical?
  print "$x\n";
}


=OUTPUT
006 + 1 = 007
007 + 2 = 009
009 + 3 = 012
012 + 4 = 016
016 + 5 = 021
021 + 6 = 027
027 + 7 = 034
034 + 8 = 042
042 + 9 = 051
051 + 10 = 061
[download]

-Blake