Abstract

This paper proposes a set of communication primitives for Haskell, to be used in open distributed systems, i.e. systems where multiple executing programs can interact using a prede ned protocol. Functions are \ rst class citizens" in a functional language, hence it would be natural transfer them between programs in a distributed system. However, existing distributed Haskell extensions are limited to closed systems or restrict the set of expressions that can be communicated. The former eectively prohibits large-scale distribution, whereas the latter sacri ces key abstraction constructs. A functional language that allows the communication of functions in an open system can be seen as a mobile computation language, hence we call our extension mHaskell (Mobile Haskell). We demonstrate how the proposed communication primitives can be used to implement more powerful abstractions, such as remote evaluation, and that common patterns of communication can be encoded as higher order functions or mobile skeletons. The design has been validated by constructing a prototype in Glasgow Distributed Haskell, and a compiled implementation is under construction.

Citations