Programming with Broadcasts.

Paper in proceeding, 1993

[Pra91, Pra92] develop CBS, a CCS-like calculus [Mil89] where processes communicate by broadcasting values along a single channel. These values are hidden or restricted by translation to noise. This paper types CBS and restricts it to processes with a unique response to each input. Non-determinism arises only if two processes in parallel both wish to transmit. These restrictions do not reduce the programming power of CBS. But strong and weak bisimulation can now be defined exactly as in CCS, yet capture observationally meaningful relations. Weak bismulation is a congruence. This paper also shows how to program in CBS in a (lazy) ML framework. A simple CBS simulator is given, and a parallel implementation discussed. The simulator represents data evaluation, recursion and conditionals directly in Lazy ML. It implements an extended CBS with evaluation as well as communication transitions.