Hooks and open points

This work is about the hook concept, as found in many Lisp Environments, and a generalization which we call open points

Paper:

The paper has been published in the book 'Quality Software - Concepts and Tools', edited by Jan Stage, Kurt NÝrmark, and Kim Guldstrand Larsen, The Software Engineering Programme, Institute for Electronic Systems, Aalborg University, Denmark.
As of now, please notice that the figures are missing in the hypertext version of the paper. They may appear in a later version.