Programming in Scheme: Learn Scheme Through Artificial Intelligence Programs

241 Pages·1996·11.59 MB·English

by  Mark Watson (auth.)

SCHEME
PROGRAMMING IN
Springer
NewYork
Berlin
Heidelberg
Barcelona
Budapest
HongKong
London
Milan
Paris
Santa Clara
Singapore
Tokyo
Mark Watson
SCHEME
PROGRAMMING IN
SCHEME
LEARN THROUGH ARTIFICIAL
INTELLIGENCE PROGRAMS
With 22Illustrations
Springer
MarkWatson
535 MarVista Drive
SolanaBeach, CA92075, USA
Coverillustration: Networkofgeometricshapes.
StevenHuntfTheImageBank
LibraryofCongressCataloginginPublicationData
Watson, Mark, 1951-
ProgramminginScheme:learnSchemethroughartificialintelligence
programs/MarkWatson.
p. cm.
Includesbibliographicalreferencesandindex.
ISBN-13:978-0-387-94681-8 e-ISBN-13:978-1-4612-2394-8
DOl:10.1007/978-1-4612-2394-8
1.Scheme(Computerprogramlanguage)2.Artificialintelligence.
I.Title.
QA76.73.S34W37 1996
005.13'3-dc20 96-10599
Printedonacid-freepaper.
© 1996Springer-VerlagNewYork,Inc.
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enue,NewYork,NY10010,USA),exceptforbriefexcerptsinconnectionwithreviewsor
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Theuseofgeneraldescriptivenames, tradenames,trademarks,etc.,inthispublication,
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names,asunderstoodbytheTradeMarksandMerchandiseMarksAct,mayaccordingly
beusedfreelybyanyone.
ProductionmanagedbyFrankGanz;manufacturingsupervisedbyJoeQuatela.
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987654321
ISBN-13:978-0-387-94681-8Springer-VerlagNewYorkBerlinHeidelberg SPIN 10524195
CONTENTS
Preface ix
Acknowledgments
Xl
CHAPTER 1 Introduction 1
CHAPTER 2 Tutorial Introduction to Scheme 3
2.1 Lists 3
2.1.1 Evaluating expressions 4
2.1.2 Listdata structures 4
2.1.3 Built-in functions for lists 7
2.2 Vectors 9
2.3 Logical tests 10
2.3.1 Testing for equality 10
2.3.2 Arithmetictests 11
2.3.3 Conditionaltests 11
2.4 Defining local variables 12
2.5 Defining functions 14
2.5.1 Recursion 17
2.6 Miscellaneous Scheme utility functions 22
CHAPTER 3 Designing for Reuse 25
3.1 Modularity 26
3.2 Cohesion in function libraries 27
3.3 Loose couplingbetween library modules 27
3.4 Example: a library for genetic algorithms 28
3.4.1 Requirements 29
3.4.2 Thedesign process 29
3.4.3 An implementation 33
3.5 Example application: allocating resources
for sales and marketing 41
3.5.1 Problem description 41
3.5.2 Method for allocating resources 41
3.5.3 Program for allocating resources 41
vi CONTENTS
CHAPTER 4 Writing PortableScheme Code 45
4.1 Designing for portability 46
4.2 Isolating operating system and graphics code 46
4.3 Aportablegraphicslibrary 47
4.4 Examplelibrary for displayinggraphstructures 52
4.5 Example: plotting Mandelbrot sets 62
4.6 Example: plotting chaoticpopulationgrowth 65
CHAPTER 5 An Iterative Approach to Analysis, Design,
and Implementation 71
5.1 Preliminaryanalysis, design, and implementation
ofa networksearchprogram 71
5.2 Evaluationofthefirst implementation
ofthe networksearchprogram 80
5.3 Improvingouranalysis, design, and implementation 80
CHAPTER 6 Neural NetworkLibrary 89
6.1 Requirements for a neural networklibrary 89
6.2 Design ofa neural networklibrary 90
6.2.1 Designing a separate libraryfor two-dimensional arrays 92
6.2.2 Algorithm for supervised learning in neural networks 92
6.3 Implementation ofa neural networklibrary 94
6.3.1 Two-dimensional arraylibrary 95
6.3.2 Neural networklibrary 99
6.4 Example application: characterrecognition 128
CHAPTER 7 Complex DataStructures 141
7.1 Using Scheme effectivelyto prototype
and testcomplexdata structures 141
7.2 Example application: naturallanguage processing 142
7.2.1 Analysis 142
7.2.2 Design 143
7.2.3 Implementation 143
CHAPTER 8 Chess Playing Program 151
8.1 Analysis 151
8.2 Design 152
8.3 Implementation 152
CHAPTER 9 Go PlayingProgram 183
9.1 Requirements andanalysis 186
9.1.1 The rules ofGo 186
9.1.2 Datastructures for maintaininginformation required
to play Go 188
9.2 Modulearchitecture 190
CONTENTS vII
9.3 Interactivelyprototypingdata structures 192
9.4 Lowlevel Scheme functions
to manipulate Godatastructures 198
9.5 Go program design 214
9.6 Go program implementation 216
9.7 Ideas for improvingthe Go playingprogram 229
APPENDIXA Installingand Running the MIT Scheme System 231
APPENDIX B More InformationAvailable onthe Internet 233
Bibliography 235
Index 237
PREFACE
Thereisa populardebate overusing Schemeorc++ toteachpro
gramming. At a recent conference a computer science professor
asked me which language was better for learning programming,
Schemeorc++ (Schemeisa modemdialectoftheLISPprogram
ming language). At the time, I had written only one LISP book
andthreec++ books, soheexpectedthatIwouldfavorc++. Ihad
to admit that I W;1S not sure which was the better language for
teaching programming. Formyown use, I like to use Scheme for
experimentingwith datastructures and exploring new ideas. For
large projects and commercial software development I use C++.
I believe that dynamic languages like Scheme are the most.ef
ficient languages to use for many programming tasks where we
want to minimize software development time rather than execu
tionspeed.InwritingthisbookIwantedtobothprovideaconcise
guide to learning the Scheme language and to demonstrate the
useofthe languagetosolveinteresting, non-trivial problemspre
sented as complete programs consisting ofreusable libraries and
application-specificcode. Byworking through this book, you will
learn the syntax of the Scheme language, control and iteration
techniques howtowriteportableand reusableSchemecode, how
touseScheme'sdynamicmemoryallocationtosimplifyrapidpro
totypingtheapplicationoftechnologieslikegeneticprogramming
and neural networks artificialintelligencetechniqueslike natural
languageprocessingefficientsearchstrategies, howto programa
computer to play chess, how to program a computerto play Go,
and effective use ofgraphics in Scheme programs.
This is a lot of material to cover in a rather short book, but
most ofwhat you will learn from this book will be the result of
yourown experimentation and modification ofthe example pro
grams. The secondchapterofthis book is a tutorial introduction
totheSchemelanguage.Thereaderisurgedtoreadthetutorialto
Scheme with the MIT Scheme (or any other Scheme implemen
tation) runningonhisorhercomputer. Thistutorialis briefsince
Schemeis a simpleprogramminglanguage, butitis importantto
readthetutorialcarefully,tryingtheexamplesasyoureadthetext.
Thetutor;aldoes notattempttocovereveryaspectofthe Scheme
programming language; rather, it covers only those elements of
the language used in the example programs in this book.
x PREFACE
This book is not an exhaustive reference for the Scheme lan
guage. Rather, the purpose ofthis book is to teach the reader to
solve interesting problems using the Scheme language. I place
moreemphasisonteachingthereaderhowto analyzea problem,
design an algorithm for solving the problem, and quickly write a
working prototypeprogramto solvethe problem. Formost prob
lems, it is important both to get a prototype program running
quickly and to design the prototype so that it can be modified
when future requirements change and also lend itself to a mod
ular implementation so that we develop reusable libraries while
solvingwhateveris today's programming problem.
This book is based on the freely distributable MIT Scheme
system, which requires Microsoft Windows 3.1, Windows 95, or
Windows NT to run. An OS/2 version of MIT Scheme is avail
able on the Internet (see Appendix B). Acopy ofa minimal MIT
Scheme development system is provided on the disks included
with this book. You can also obtain new versions of the MIT
Schemesystem,aswellasanEmacs-likeeditorandanativemode
compiler, from various Internet FTP sites listed in Appendix B
(e.g., ftp.cs.cmu.edu and ftp.cs.indiana.edu).
I also use and recommend three otherpublic domain Scheme
implementations:
MacGambit Scheme onthe Macintosh PC Scheme from Texas
Instruments, now in the public domain SCM Scheme, with
versions for DOS, OS/2, and UNIX
SomeoftheexamplesinthisbookrelyonMITScheme-specific
functions thatare not partofthe Scheme language standard: the
chessplayingprogramusestheMITSchemesortfunction,andthe
geneticalgorithmandneuralnetworkexamplesrequirea random
numbergenerator.
The source code and executables of MIT Scheme are freely
availableonthe Internet.
MarkWatson
SolanaBeach, California
[email protected]
[email protected]
ACKNOWLEDGMENTS
Iwouldliketothankmywife, Carol, forherencouragementwhile
Iwaswritingthisbook.IwouldliketothankbothGuyLewisSteel
Jr. and Gerald J. Sussman, who designed and first implemented
the Scheme language. I would like to thank the team at MIT for
writing the MIT Scheme development system, which is included
with this book. I would like to thank my editor, Martin Gilchrist,
bothfor recommending thisprojectandforhisencouragement. I
wouldliketothankmyproductioneditorFrankGanzandmycopy
editorDavidKramer. Iwouldliketo thankmytechnical reviewer,
Jonathan Rossie, for manysuggested improvements.