It is important to be able to structure and classify open points, as well as all other kinds of definitions, in a Lisp program. The need for structure on the open points becomes especially urgent when making tools that support the handling of open points. In traditional Lisps, where the structuring mechanisms are weak, it is therefore tempting to invent conventions that impose some structure on the open points. In the concrete framework described above, the hook identifier may be of the form group:name, where group defines a unit of structuring to which the hook belong. This may, of course, be generalized to two or more levels of grouping if necessary. In Lisps that are stronger on overall structuring mechanisms, e.g., Common Lisp or CLOS, it is natural to use the existing structuring mechanisms (packages and classes) for open points as well.