An Asynchronous Message Passing and Concurrent Scheme Implementation

This thesis investigates the power of a Scheme implementation extended with processes using an asynchronous message passing style very much in common with the functional programming language Erlang. Patterns and pattern matching have been added to the language in order to support out of order message selection. Each process is equipped with a local heap to store its local data and a single global heap contains the shared data of all processes reducing the potential bottleneck of local garbage collection. We will show by examples that this implementation of Scheme improves the expressiveness of the language compared to Erlang and that lambda abstractions and continuations are fruitful elements for concurrent programming. In particular we will show how to make representation independent data protocols and how to migrate recursive computations. Contents 1 Introduction 4 1.1 Scheme -- an Appropriate Choice . . . . . . . . . . . . . . . . . . 4 2 The Language 6 2.1 Patterns . . . . . ...