Programming Open Distributed Systems in Maude

Maude is a high-performance logical framework based on rewriting logic and supporting formal specification, verification and declarative programming of concurrent systems. Since most concurrent open systems are made up of actor-like objects that communicate with each other through message passing, Maude provides special features to support their specification, verification and programming. Since open systems are heterogeneous, involving widely different kinds of objects such as sensors, actuators, devices, databases, graphical user interfaces, and so on, Maude supports declarative message-passing interaction between Maude objects and a wide variety of heterogeneous external objects. In this paper we explain and illustrate a methodology where an open system can first be designed and verified in Maude and then implemented as a distributed system of heterogeneous objects in a way that seamlessly bridges the gap between its formal specification and verification and its distributed implementation.