Introduction

Prolog is a simple but powerful programming language developed at the University of Marseille [Roussel 75], as a practical tool for programming in logic [Kowalski 74]. From a user’s point of view the major attraction of the language is ease of programming. Clear, readable, concise programs can be written quickly with few errors.

For an introduction to programming in Prolog, readers are recommended to consult [Sterling & Shapiro 86]. However, for the benefit of those who do not have access to a copy of this book, and for those who have some prior knowledge of logic programming, we include a summary of the language. For a more general introduction to the field of Logic Programming see [Kowalski 79]. See Prolog Intro.

This manual describes a Prolog system developed at the Swedish Institute of Computer Science. Parts of the system were developed by the project “Industrialization of SICStus Prolog” in collaboration with Ericsson Telecom AB, NobelTech Systems AB, Infologics AB and Televerket. The system consists of a WAM emulator written in C, a library and runtime system written in C and Prolog and an interpreter and a compiler written in Prolog. The Prolog engine is a Warren Abstract Machine (WAM) emulator [Warren 83]. Two modes of compilation are available: in-core i.e. incremental, and file-to-file. When compiled, a predicate will run about 8 times faster and use memory more economically. Implementation details can be found in [Carlsson 90] and in several technical reports available from SICS.

SICStus Prolog follows the mainstream Prolog tradition in terms of syntax and built-in predicates. As of release 4, SICStus Prolog is fully compliant with the International Standard ISO/IEC 13211-1 (PROLOG: Part 1—General Core) and the subsequent Technical Corrigenda 1, 2 and 3.