MOPping it up
Building a simple Metaobject-Protocol
Many languages make a distinction between objects and classes. But shouldn't everything – including classes – be an object in a pure object-oriented language? Some languages like Smalltalk, Common Lisp, and Ruby manage just that and offer a complete and flexible Metaobject-Protocol. Others such as Java only offer a read-only object protocol commonly called “introspection” or “reflection”.