Method modifiers are a powerful feature from the CLOS (Common Lisp Object
System) world.

In its most basic form, a method modifier is just a method that calls
$self->SUPER::foo(@_). I for one have trouble remembering that exact
invocation, so my classes seldom re-dispatch to their base classes. Very bad!

Class::Method::Modifiers provides three modifiers: before, around, and after.
before and after are run just before and after the method they modify, but can
not really affect that original method. around is run in place of the original
method, with a hook to easily call that original method.

One clear benefit of using Class::Method::Modifiers is that you can define
multiple modifiers in a single namespace. These separate modifiers don't need
to know about each other. This makes top-down design easy. Have a base class
that provides the skeleton methods of each operation, and have plugins modify
those methods to flesh out the specifics.

In short, Class::Method::Modifiers solves the problem of making sure you call
$self->SUPER::foo(@_), and provides a cleaner interface for it.

WWW: http://search.cpan.org/dist/Class-Method-Modifiers/