The Class::XSAccessor::Array module implements fast XS accessors both
for getting at and setting an object attribute. Additionally, the module
supports mutators and simple predicates (has_foo() like tests
for definedness of an attributes). The module works only with objects that
are implemented as arrays.

A simple benchmark showed more than a factor of two performance advantage over
writing accessors in Perl.

WWW: http://search.cpan.org/dist/Class-XSAccessor-Array/