README.md

This is an open-source repository for the book Paradigms of Artificial Intelligence Programming: Case Studies in Common Lisp by Peter Norvig (1992), and the code contained therein. The copyright has reverted to the author, who has shared it here under MIT license. On the list of most influential books for programmers. As seen on TV. See also: errata, comments, retrospective.

The book is available in these formats:

• pdf: see releases for a scanned version
• text: PAIP.txt (from OCR'ing the scanned pdf, containing many errors)
• epub: see releases for a cleaned up version downloaded from Safari (much cleaner than the scanned versions)
• and chapter?.md markdown files:

Table of Contents

• Paradigms of Artificial Intelligence Programming
  • Front matter
  • Preface
• Part I: Introduction to Common Lisp
  • 1 Introduction to Lisp
  • 2 A Simple Lisp Program
  • 3 Overview of Lisp
• Part II: Early AI Programs
  • 4 GPS: The General problem Solver
  • 5 Eliza: Dialog with a Machine
  • 6 Building Software Tools
  • 7 Student: Solving Algebra Word Problems
  • 8 Symbolic Mathematics: A Simplification Program
• Part III: Tools and Techniques
  • 9 Efficiency Issues
  • 10 Low-Level Efficiency Issues
  • 11 Logic Programming
  • 12 Compiling Logic programs
  • 13 Object-Oriented Programming
  • 14 Knowledge Representation and Reasoning
• Part IV: Advanced AI Programs
  • 15 Symbolic Mathematics with Canonical Forms
  • 16 Expert Systems
  • 17 Line-Diagram Labeling by Constraint Satisfaction
  • 18 Search and the Game of Othello
  • 19 Introduction to Natural Language
  • 20 Unification Grammars
  • 21 A Grammar of English
• Part V: The Rest of Lisp
  • 22 Scheme: An Uncommon Lisp
  • 23 Compiling Lisp
  • 24 ANSI Common Lisp
  • 25 Troubleshooting

The Lisp Files

The Lisp code files are listed here:

CH	Filename	Description
-	examples.lisp	A list of example inputs taken from the book
-	tutor.lisp	An interpreter for running the examples
-	auxfns.lisp	Auxiliary functions; load this before anything else
1	intro.lisp	A few simple definitions
2	simple.lisp	Random sentence generator (two versions)
3	overview.lisp	14 versions of LENGTH and other examples
4	gps1.lisp	Simple version of General Problem Solver
4	gps.lisp	Final version of General Problem Solver
5	eliza1.lisp	Basic version of Eliza program
5	eliza.lisp	Eliza with more rules; different reader
6	patmatch.lisp	Pattern Matching Utility
6	eliza-pm.lisp	Version of Eliza using utilities
6	search.lisp	Search Utility
6	gps-srch.lisp	Version of GPS using the search utility
7	student.lisp	The Student Program
8	macsyma.lisp	The Macsyma Program
8	macsymar.lisp	Simplification and integration rules for Macsyma
9-10	auxfns.lisp	Auxiliary functions
11	unify.lisp	Unification functions
11	prolog1.lisp	First version of Prolog interpreter
11	prolog.lisp	Final version of Prolog interpreter
12	prologc1.lisp	First version of Prolog compiler
12	prologc2.lisp	Second version of Prolog compiler
12	prologc.lisp	Final version of Prolog compiler
12	prologcp.lisp	Primitives for Prolog compiler
13	clos.lisp	Some object-oriented and CLOS code
14	krep1.lisp	Knowledge Representation code: first version
14	krep2.lisp	Knowledge Representation code with conjunctions
14	krep.lisp	Final KR code: worlds and attached functions
15	cmacsyma.lisp	Efficient Macsyma with canonical form
16	mycin.lisp	The Emycin expert system shell
16	mycin-r.lisp	Some rules for a medical application of emycin
17	waltz.lisp	A Line-Labeling program using the Waltz algorithm
18	othello.lisp	The Othello playing program and some strategies
18	othello2.lisp	Additional strategies for Othello
18	edge-tab.lisp	Edge table for Iago strategy
19	syntax1.lisp	Syntactic Parser
19	syntax2.lisp	Syntactic Parser with semantics
19	syntax3.lisp	Syntactic Parser with semantics and preferences
20	unifgram.lisp	Unification Parser
21	grammar.lisp	Comprehensive grammar of English
21	lexicon.lisp	Sample Lexicon of English
22	interp1.lisp	Scheme interpreter, including version with macros
22	interp2.lisp	A tail recursive Scheme interpreter
22	interp3.lisp	A Scheme interpreter that handles call/cc
23	compile1.lisp	Simple Scheme compiler
23	compile2.lisp	Compiler with tail recursion and primitives
23	compile3.lisp	Compiler with peephole optimizer
23	compopt.lisp	Peephole optimizers for compile3.lisp

Running the Code

There is no single "application" to run. Rather, there is a collection of source code files, duplicating the code in the book. You can read and/or run whatever you like. Lisp is an interactive language, and you will need to interact with the code to get benefit from it. Some hints:

• You will need a Common Lisp interpreter/compiler/environment. Here's a discussion of the options.
• You will always need (load "auxfns.lisp").
• You will need (requires "file"), for the various instances of file that you want to use. (If requires does not work properly on your system you may have to alter its definition, in auxfns.lisp.
• The function do-examples, which takes as an argument either :all or a chapter number or a list of chapter numbers, can be used to see examples of the use of various functions. For example, (do-examples 1) shows the examples from chapter 1. Access this by doing (requires "examples").

Other resources

• I wrote a retrospective on the book in 2002.
• There is a nice Python version of the code, by Daniel Connelly at Georgia Tech, supervised by Ashok Goel.