Composing Event-B Specifications - Case-Study Experience

Event-B is a formal method, based on set theory and firstorder logic, for specification and verification of reactive systems supported by the Rodin tool kit. Feature modelling is a well-known technique for managing variability and configuring products within software product lines (SPLs). Our objective is to explore whether we can use existing Event-B composition techniques and tooling for feature-based product line development. If case-study experiments reveal these mechanisms to be inadequate, then they also should suggest further research directions. The main objective is to maximise the amount of reuse. This includes avoiding as far as possible having to reprove a composed specification when the models being composed have already been proven. We have modelled two case-studies in Event-B using both horizontal and vertical refinements. This work contributes by analysing existing tools and techniques in Event-B for feature-based development, exploring composition related issues by modelling example case-studies and suggesting further tooling requirements.