The Perl 5 module Class::InsideOut s a simple, safe and streamlined
toolkit for building inside-out objects. Unlike most other inside-out
object building modules already on CPAN, this module aims for
minimalism and robustness:

    * Does not require derived classes to subclass it
    * Uses no source filters, attributes or CHECK blocks
    * Supports any underlying object type including black-box inheritance
    * Does not leak memory on object destruction
    * Overloading-safe
    * Thread-safe for Perl 5.8.5 or better
    * mod_perl compatible
    * Makes no assumption about inheritance or initializer needs

It provides the minimal support necessary for creating safe inside-out
objects and generating flexible accessors.