libinternals-perl binary package in Ubuntu Precise i386

 Internals allows you to write-protect and write-enable your Perl variables,
 objects and data structures.
 .
 Moreover, the reference count of any Perl variable can be read and set.
 .
 You can never pass the object directly on which to perform the desired
 action, you always have to pass a reference to the variable or data structure
 in question.
 .
 This comes in handy for objects and anonymous data structures, where you only
 have a reference anyway!

Source package