* Implement class Foo;
* Only set up the matching declarators inside of class and role.
(i.e. no augment in role)
* Implemet subclass { ... }, meaning class Foo extends OuterClass { ... } for
nested classes.
* Allow $class = extends Foo { ... }; and $class = with Role { ... }; for
creating anonymous classes. Not only $class = class extends Foo { .. };
doesn't read very well, it's also hard to distinguish from creating a class
called 'extends'