COMMON LISP:
A Gentle Introduction
to Symbolic Computation
COMMON LISP:
A Gentle Introduction
to Symbolic Computation
David S. Touretzky
Carnegie Mellon University
The Benjamin/Cummings Publishing Company,Inc.
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Sponsoring Editor: Alan Apt
Developmental Editor: Mark McCormick
Production Coordinator: John Walker
Copy Editor: Steven Sorenson
Text and Cover Designer: Michael Rogondino
Cover image selected by David S. Touretzky
Cover: La Grande Vitesse, sculpture by Alexander Calder
Copyright (c) 1990 by Symbolic Technology, Ltd.
Published by The Benjamin/Cummings Publishing Company, Inc.
This document may be redistributed in hardcopy form only, and only for
educational purposes at no charge to the recipient. Redistribution in
electronic form, such as on a web page or CD-ROM disk, is prohibited.
All other rights are reserved. Any other use of this material is prohibited
without the written permission of the copyright holder.
The programs presented in this book have been included for their
instructional value. They have been tested with care but are not
guaranteed for any particular purpose. The publisher does not offer any
warranties or representations, nor does it accept any liabilities with
respect to the programs.
Library of Congress Cataloging-in-Publication Data
Touretzky, David S.
Common LISP : a gentle introduction to symbolic computation /
David S. Touretzky
p. cm.
Includes index.
ISBN 0-8053-0492-4
1. COMMON LISP (Computer program language) I. Title.
QA76.73.C28T68 1989
005.13’3–dc20
89-15180
CIP
ISBN 0-8053-0492-4
ABCDEFGHIJK - DO - 8932109
The Benjamin/Cummings Publishing Company, Inc.
390 Bridge Parkway
Redwood City, California 94065
To Phil and Anne
vii
Preface
This book is about learning to program in Lisp. Although widely known as
the principal language of artificial intelligence resear