Concurrent Programming in Haskell

In this paper, an extension of the non-strict functional language Haskell 3] is presented. It performs the evaluation of expressions by using multiple threads. The synchronous model and the event interface used are similar to Reppy's CML 11], but in this case we must deal with new factors like non-strictness, embedding the synchronous operations into the IO monad. Lazy structures are useful to model the behaviour of processes, in the same way as Hoare's traces in CSP 5]. A great attention is paid to higher-order concurrent abstractions which simplify programmer's work. A prototype implementation has been developed in Yale Haskell.