Concurrent Flexible Reversibility

Concurrent reversibility has been studied in different areas, such as biological or dependable distributed systems. However, only "rigid" reversibility has been considered, allowing to go back to a past state and restart the exact same computation, possibly leading to divergence. In this paper, we present croll-pi, a concurrent calculus featuring flexible reversibility, allowing the specification of alternatives to a computation to be used upon rollback. Alternatives in croll-pi are attached to messages. We show the robustness of this mechanism by encoding more complex idioms for specifying flexible reversibility, and we illustrate the benefits of our approach by encoding a calculus of communicating transactions.