Paraphrased from the Data:Swap's documentation ... Data::Swap (XS) module allows to swap the contents of two referenced variables, even if they have different types. The main application is to change the base type of an object after it has been created, for example for dynamic loading of data structures: swap $self, bless $replacement, $newclass; WWW: http://search.cpan.org/dist/Data-Swap/