Formalizing the semantics of variants

Software Configuration Management (SCM) is the activity of controlling the evolution of a software System. Our goal is to give a precise semantics to SCM concepts in order to form a sound basis for developing improved SCM tools. We are beginning by focusing on the key notion of version. In particular, we are trying to understand the semantics of variants--versions of a configuration item that are equivalent in some context. In this paper we give a formal semantics for variants based on the notion of pre-order relation, as opposed to the more familiar notion of equivalence. Such an approach allows consistent modifications of interfaces to he taken into account. We also present an initial mapping of those semantics onto an object-oriented persistent programming language that can be used to model an SCM repository