Feature Composition – Towards product lines of Event-B models

Event-B is a formal language for modelling reactive systems, based on set theory and first-order logic. The RODIN toolkit provides comprehensive tool support for modelling and refinement in Event-B, analysis and verification using animator/model-checkers and theorem provers. We consider the need to support reuse, in particular product line reuse, in such a formal development method. Feature modelling is an established technique for reuse in product lines. We introduce concepts of feature modelling and composition in Event-B to support the reuse of formal models and developments. A prototype feature composition tool has been developed (as a RODIN plugin) for Event-B, based on the Eclipse Modelling Framework (EMF). Using an MDD philosophy, the tool extends the Event-B language metamodel to a composition metamodel, and implements prototype composition patterns for Event-B features. Thus, a required composite model can be constructed by selecting, specializing, and composing input features in a defined way. The tool is the first step towards full feature modelling for product line model reuse for Event-B. We describe future work required to meet this goal.