ANSI common lisp. / Paul Graham - 7Chan

450 Pages·2007·5.85 MB·English

ANSI
Common Lisp
PRENTICE HALL SERIES
UW§ IN ARTIFICIAL INTELLIGENCE
Stuart Russell and Peter Norvig, Editors
GRAHAM ANSI Common Lisp
MUGGLETON Logical Foundations of Machine Learning
RUSSELL & NORVIG Artificial Intelligence: A Modern Approach
ANSI
Common Lisp
Paul Graham
An Alan R. Apt Book
Prentice Hall, Upper Saddle River, New Jersey 07458
Library of Congress Cataloging-in-Publication Data
Graham, Paul.
ANSI common lisp. / Paul Graham.
p. cm.
"An Alan R. Apt book."
Includes bibliographical references and index.
ISBN 0-13-370875-6
1. COMMON LISP (Computer program language) I. Tide.
QA76.73.C28G69 1996
005.13'3-dc20 95-45017
CIP
Publisher: Alan Apt
Production Editor: Mona Pompili
Cover Designer: Gino Lee
Copy Editor: Shirley Michaels
Production Coordinator: Donna Sullivan
Editorial Assistant: Shirley McGuire
Cover Photo: Ed Lynch
•m
© 1996 by Prentice Hall, Inc.
Upper Saddle River, NJ 07458
The author and publisher of this book have used their best efforts in preparing this book.
These efforts include the development, research, and testing of the theories and programs
to determine their effectiveness. The author and publisher shall not be liable in any event
for incidental or consequential damages in connection with, or arising out of, the furnishing,
performance, or use of these programs.
All rights reserved. No part of this book may be reproduced, in any form or by any means,
without permission in writing from the publisher.
All trademarks are the property of their respective owners.
Printed in the United States of America
20
ISBN 0-13-370875-6
Prentice-Hall International (UK) Limited, London
Prentice-Hall of Australia Pty. Limited, Sydney
Prentice-Hall of Canada, Inc., Toronto
Prentice-Hall Hispanoamericana, S. A., Mexico
Prentice-Hall of India Private Limited, New Delhi
Prentice-Hall of Japan, Inc., Tokyo
Prentice-Hall Asia Pte. Ltd., Singapore
Editora Prentice-Hall do Brasil, Ltda., Rio de Janeiro
TORTM
Half lost on my firmness gains to more glad heart,
Or violent and from forage drives
A glimmering of all sun new begun
Both harp thy discourse they march'd,
Forth my early, is not without delay;
For their soft with whirlwind; and balm.
Undoubtedly he scornful turn'd round ninefold,
Though doubled now what redounds,
And chains these a lower world devote, yet inflicted?
Till body or rare, and best things else enjoy'd in heav'n
To stand divided light at ev'n and poise their eyes,
Or nourish, lik'ning spiritual, I have thou appear.
—Henley
Preface
The aim of this book is to teach you Common Lisp quickly and thoroughly.
It is really two books. The first half is a tutorial that explains, with plenty of
examples, all the essential concepts of Lisp programming. The second half
is an up-to-date summary of ANSI Common Lisp, describing every operator
in the language.
Audience
ANSI Common Lisp is intended for both students and professional program
mers. It assumes no prior knowledge of Lisp. Experience writing programs
in some other language would be helpful, but not absolutely necessary. The
book begins with the most basic concepts, and pays special attention to the
points that tend to confuse someone seeing Lisp for the first time.
This book could be used by itself as the textbook in a course on Lisp
programming, or to teach Lisp as part of a course on artificial intelligence or
programming languages. Professional programmers who want to learn Lisp
will appreciate the direct, practical approach. Those who already use Lisp
will find it a useful source of examples, and a convenient reference for ANSI
Common Lisp.
How to Use This Book
The best way to learn Lisp is to use it. It's also more fun to learn a language
by writing programs in it. This book is designed to get you started as quickly
as possible. After a brief Introduction,
vii
viii PREFACE
• Chapter 2 explains, in 21 pages, everything you need to start writing
Lisp programs.
• Chapters 3-9 introduce the essential elements of Lisp programming.
These chapters pay special attention to critical concepts like the role
of pointers in Lisp, the use of recursion to solve problems, and the
significance of first-class functions.
For readers who want a thorough grounding in Lisp techniques,
• Chapters 10-14 cover macros, CLOS, operations on list structure, opti
mization, and advanced topics like packages and read-macros.
• Chapters 15-17 sum up the lessons of the preceding chapters in three
examples of real applications: a program for making logical inferences,
an HTML generator, and an embedded language for object-oriented
programming.
The last part of the book consists of four appendices, which should be useful
to all readers:
• Appendices A-D include a guide to debugging, source code for 58
Common Lisp operators, a summary of the differences between ANSI
Common Lisp and previous versions of the language,0 and a reference
describing every operator in ANSI Common Lisp.
The book concludes with a section of notes. The notes contain clarifications,
references, additional code, and occasional heresies. Notes are indicated in
the text by a small circle, like this.0
The Code
Although it describes ANSI Common Lisp, this book has been designed so
that you can use it with any version of Common Lisp. Examples that depend
on newer features are usually accompanied by notes showing how they would
be rendered in older implementations.
All the code in this book is available online. You can find it, along with
links to free software, historic papers, the Lisp FAQ, and a variety of other
resources, at:
http://www.eecs.harvard.edu/onlisp/
The code is also available by anonymous FTP from:
ftp://ftp.eecs.harvard.edu:/pub/onlisp/
Questions and comments can be sent to pgOeecs. harvard. edu.
PREFACE IX
On Lisp
Throughout this book I've tried to point out the unique qualities that make
Lisp Lisp, and the new things that this language will let you do. Macros,
for example: Lisp programmers can, and often do, write programs to write
their programs for them. Lisp is the only major language in which this is a
routinely used technique, because Lisp is the only major language to provide
the abstractions that make it convenient. I would like to invite readers who
are interested in learning more about macros and other advanced techniques
to read the companion volume, On Lisp.
Acknowledgements
Of all the friends who have helped me during the writing of this book, I owe
special thanks to Robert Morris. The whole book reflects his influence, and is
very much the better for it. Several of the examples are derived from programs
he originally wrote, including Henley (page 138) and the pattern-matcher on
page 249.
I was fortunate to have a first-rate team of technical reviewers: Skona
Brittain, John Foderaro, Nick Levine, Peter Norvig, and Dave Touretzky.
There is hardly a page of the book that did not benefit in some way from their
suggestions. John Foderaro even rewrote some of the code in Section 5.7.
Several other people consented to read all or part of the manuscript,
including Ken Anderson, Tom Cheatham, Richard Fateman, Steve Hain,
Barry Margolin, Waldo Pacheco, Wheeler Ruml, and Stuart Russell. Ken
Anderson and Wheeler Ruml, in particular, made many useful comments.
I'm grateful to Professor Cheatham, and Harvard generally, for providing
the facilities used to write this book. Thanks also to the staff at Aiken Lab,
including Tony Hartman, Dave Mazieres, Janusz Juda, Harry Bochner, and
Joanne Klys.
I'm glad to have had the chance to work with Alan Apt again. The
people at Prentice Hall—Alan, Mona Pompili, Shirley McGuire, and Shirley
Michaels—are really a pleasure to work with.
The cover is again the work of the incomparable Gino Lee, of the Bow &
Arrow Press, Cambridge.
This book was typeset using L^TgX, a language written by Leslie Lamport
atop Donald Knuth's Tj3C, with additional macros by L. A. Carr, Van Jacobson,
and Guy Steele. The diagrams were done with Idraw, by John Vlissides and
Scott Stanton. The whole was previewed with Ghostview, by Tim Theisen,
which is built on Ghostscript, by L. Peter Deutsch.
I owe thanks to many others, including Henry Baker, Kim Barrett, Ingrid
Bassett, Trevor Blackwell, Paul Becker, Gary Bisbee, Frank Deutschmann,
Frances Dickey, Rich and Scott Draves, Bill Dubuque, Dan Friedman, Jenny