Instructors' Guide

1. The letter/envelope idiom is a means to separate interface aspects of a class from implementation aspects. An advantage is that implementations may be dynamically changed.
2. Polymorphism may be characterized as the ability to be of a different type, dependent upon circumstances. For object-oriented languages, the best-known form is (inclusion) polymorphism by inheritance. However, (ad hoc) polymorphism, due to function overloading, is a facility found in many languages.
3. See section canonical.
4. See section hush-idioms. - We can distinguish between creational, structural and behavioral patterns. For a discussion of their relevance see section Patterns.
5. See section Behavioral. - The Reactor pattern describes how to deal with events, in particular when multiple event loops are involved. See section Reactor.
6. See section events.