Combinators for Message-Passing in Haskell

Much code in message-passing programs is tedious, verbose wiring code. This code is error prone and laborious - and tends to be repeated across many programs with only slight variations. By using type-classes, higher-order and monadic functions in Haskell, most of this code can be captured in re-usable high-level combinators that shorten and simplify message-passing programs. We motivate the design and use of these combinators via an example of a concurrent biological simulation, and explain their implementation in the Communicating Haskell Processes library.