First-class change objects for feature-oriented programming

A growing trend in software construction advocates the encapsulation of software building blocks as features which better match the specification of requirements. As a result, programmers find it easier to design and compose different system variations. Feature-oriented programming (FOP) is the research domain that targets this trend. We argue that the state-of-the-art approaches to FOP lack expressiveness because they specify a feature as a set of building blocks rather than a transition that has to be applied on a system in order to add that feature's functionality to the system.
We propose to specify features as sets of first-class change objects which can add, modify or delete building blocks to or from a software system. We present ChEOPS, a proof-of-concept implementation of this approach and use it to show how our approach contributes to FOP on three levels: expressiveness, composition verification and bottom-up FOP.