Excellent! And for those who look at the code and are totally lost, here is a useful hint on how tie works. All that tie does is allow an object in a class that defines the right methods to look like a native Perl datatype. The only thing you have to do is make sure that you are providing the OO interface that Perl is looking for.

To find out what methods are part of the interface that Perl knows to look for type "perldoc -f tie". Note that the documentation here of tie is somewhat misleading since it documents the limitations of tie that were in Perl 5.003. For instance you probably can create a full tied interface to an array.

It feels strange the first few times you create an implementation of a tied class, but it really is not very hard and it is an excellent example of how encapsulation can lead to good things later. :-)