Evolution Styles: Change Patterns for Software Evolution

Patterns have been proved useful in many problem domains. In the domain of software evolution, only behaviour-preserving patterns (e.g. re-factorings) have ever been proposed. This paper proposes to broaden the scope of change patterns by means of a reification of any evolution efforts into styles. The authors define an evolution style as a first-class entity which is specified once and can be applied many times. Evolution styles allow the specification of (non) behaviour-preserving change patterns. They exemplify the use of the evolution style concept by means of two applications which evolve in a style-based way.