First. Thanks for being the first to post a real application.

I going to assume that what you are doing is passing the blessed handles to live (populated) instance of hash(or array)-based objects to yaml, and having it return a string that contains:

1. The name of the class;
2. The attribute name/current value pairs of the instance.

In essence, exactly the same as passing a hash to Data::Dumper, Data::Dump, Data::Dumper::Serial.

This is a convenient side-effect of using Perl's hashes as the basis of OO. And it's not something that I would want to give up. Indeed, it's one of two primary reasons for my eshewing InsideOut implementations. Forcing the user to hack the source on those rare occasions when it it necessary to look inside an object simply are not worth the loss of convenience, all the extra work or the abysmal performance.

But, it is only a convenience. It is perfectly possible to serialise (say) an inside-out object, or as I used once for a application that needed millions of instances and I needed to save space, a blessd scalar containing a packed string of the instance data. You simply have to provide a toString() and fromString(), or STORABLE_freeze() STORABLE_thaw() methods in each of your classes. Extra work, but perfectly doable.

With things like Moose and Class::Std (if your that way inclined), or many of the other OO frameworks, these can (or could) even be generated for you from the Class definition.

So, whilst convenient, useful and very usable, this use case doesn't contradict my premise.