package Foo; use base qw(Class::Accessor::Faster);
Class::Accessor's generated accessors require two method calls to accomplish their task (one for the accessor, another for get() or set()).
Class::Accessor::Fast eliminates calling set()/get() and does the access itself, resulting in a somewhat faster accessor.
Class::Accessor::Faster uses an array reference underneath to be faster.
Read the documentation for Class::Accessor for more info.
This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself. That means either (a) the GNU General Public License or (b) the Artistic License.