Multicast - Observer ≠ Typed Message LePUS - A Formal Language for Negotiating Design Patterns: A Case Study

A discussion was chronicled in previous issues of C++ Report comparing three [candidate] patterns: OBSERVER, MULTICAST, and TYPED MESSAGE. The comparison took a number of pages to be conveyed, mostly using informal means or concrete instances. We use a formal pattern specification language LePUS to define each design pattern and to illuminate the difference between the three. We translate each diagram to predicate calculus to establish their relationship, thereby demonstrating how LePUS can in general serve in the study of design patterns.