OPAL: Design and implementation of an algebraic programming language

Abstract

The algebraic programming language OPAL has been designed as a testbed for experiments with the specification and development of functional programs. The language shall in particular foster the (formal) development, of productionquality software that is written in a purely flmctional style. As a consequence, OPAL molds concepts from Algebraic Specification and Functional Programming into a unified framework. The amalgamation of these two concepts which are both based on a sound theoretical foundation constitutes an ideal setting for the construction of formally verified safe software. Moreover, the high level of abstraction and the conceptual clarity of the functional style can increase the productivity of software development significantly. Unfortunately, the acceptance of the functional style suffers from the widespread prejudice that its advantages are paid for by a high penalty in runtime and storage consumption. Yet, this is not, true. Due to their semantic elegance and clarity, functional programs are amenable to a wide variety of powerful optimizations, such that the programmer need not be concerned with low-level considerations about machine pecularities. This way, she can concentrate on finding good algorithmic solutions instead. The potential for automatic optimizations is highly increased, when functional programs are combined with algebraic specifications. Then, algebraic properties of the flmctional programs can be used to guide optimizations which go far beyond traditional optimization techniques. In this paper we illustrate some principles of algebraic programming. Moreover, we introduce the language OPAL, sketch its compilation strategies, and point out some challenges for further research in the area of algebraic programming languages.