Since the dawning of design patters, various attempts have been made to
develop methods that can formalize these patterns. The benefits of
formalization are know, but the challenge is to develop a method that is
expressive enough to capture the abstract structure and behavior and at the
same time is flexible enough to support instantiation of a pattern in
In this talk I will introduce the formalization methods Disco (Distributed
Co-operation) and PCL (Pattern Contract Language) and discuss the
differences and similarities between them.