Implementation of a declarative state‐transition system

A declarative programming style is claimed to have significant advantages from a software engineering point of view. However, these benefits cannot generally be realized when writing programs that are concerned with changing state, such as environments and programming tools. Declarative state‐transition (DST) systems have been proposed as a solution to this problem. In DST systems, computation and update are separated. Programs are interpreted as defining functions or relations over states, and update follows successful computation of new states. Support for persistent state and atomic, serializable transactions facilitates the implementation of programming environments and tools. This paper describes an implementation scheme for DST systems. The scheme is illustrated by a presentation of the implementation of PPS, a DST system for parallel logic programming.