Coordination language for distributed clean

Abstract

The distributed evaluation of functional programs and the communication between computational nodes require high-level process description and coordination mechanism. This paper presents the D-Clean high-level functional language, which supports the distributed computation of Clean functions over a cluster. The lazy functional programming language Clean is extended by new language elements in order to achieve parallel features. The distributed computations of functions are expressed in the form of process-networks. D-Clean introduces language primitives to control the dataflow in a distributed process-network. A process scheme defines a partial computation graph, where the nodes are functions to be evaluated and the edges are communication channels. The computational nodes are implemented as statically typed Clean programs. The schemes are parameterized by functions, types and data for defining process networks. D-Clean is compiled to an intermediate level language called D-Box. The D-Clean generic constructs are instantiated into D-Box expressions. D-Box is designed for the description of the computational nodes. D-Box expressions hide implementation details and enable direct control over the process-network. The asynchronous communication is based on language-independent middleware services. The present paper provides the syntax and the informal semantics of both coordination languages. To illustrate the definition of a distributed functional computational pattern using the D-Clean language a farm skeleton running example is presented.