MIT Artificial Intelligence Laboratory

386 Pages·2012·47.03 MB·English

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MIT Artificial Intelligence Laboratory
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DRAFT: 31 JULY 1983 i
Table of Contents
1. Building Abstractions with Procedures 7
1.1. The Elements of Programming 9
1. 1 1. Expressions 10
1.1.2. Naming and the Environment 12
1.1.3. Evaluating Combinations 13
1.1 4. Compound procedures 16
1.1 5. The Substitution Model for Procedure Evaluation 18
1.1.6. Conditional Expressions and Predicates 20
1.1.7. Example: Square Roots by Newton's Method 23
1. 1.8. Procedures as Black-Box Abstractions 26
1.2. Procedures and the Processes they Generate 30
1.2.1. Linear Recursion and Iteration 31
1.2.2. Tree Recursion 35
1,2.3. Orders of Growth 39
1.2.4. Exponentiation 40
1.2.5. Greatest Common Divisors 42
1.2.6. Example: Testing for Primality 44
1.3. Formulating Abstractions with Higher Order Procedures 48
1.3.1. Procedures as Parameters 49
1.3.2. Constructing Procedures using LAMBDA 52
1.3.3. Procedures as General Methods 56
1.3.4. Procedures as Returned Values 61
2. Building Abstractions with Data 65
2.1. Introduction to Data Abstraction 68
2.1.1. Example: Arithmetic Operators for Rational Numbers 68
2,1.2. Abstraction Barriers 72
2.1.3. What is Data'.) 74
2.1.4. Example: Interval Arithmetic 76
2.2. Hierarchical Data 79
2.2.1. Representing Sequences 80
2.2.2. Representing Trees 85
2.2.3. Symbolic Expressions; The Need for QUOTE 88
2.2.4. Example: Symbolic Differentiation 91
2.2.5. Example: Representing Sets 95
2.2.6. Example: Huffman Encoding Trees 102
2.3. Multiple Representations for Abstract Data 109
2.3. 1. R presentations for Complex Numbers
2.3.2. Manifest Types 114
2.3.3. Data-directed Programming 118
2.4. Systems with Generic Operators 122
. H DRAFT: 31 JULY 1983 Table of Contents
2.4.1. Generic Arithmetic Operators 123
2.4.2. Combining Operands of Different Types 126
2.4.3. Example: Symbolic Algebra 131
3. Modularity, Objects, and State 143
3.1. Assignment and Local State 144
3.1.1. Local State Variables 144
3.1.2. The Costs of Introducing Assignment 149
3.1.3. The Benefits of Introducing Assignment 153
3.2. The Environment Model of Evaluation 156
3.2.1. The Rules for Evaluation 157
3.2.2. Evaluating Simple Procedures 160
3.2.3. Frames as the Repository of Local State 162
3.2.4. Internal Definitions 167'
3.3. Modeling with Mutable Data 170
3.3.1. Mutable List Structure 170
3.3.2. Representing Queues 178
3.3.3. Representing Tables 182
3.3-4 A Simulator for Digital Circuits 186
3.3.5. Propagation of Constraints 196
3.4. Stream Processing 205
3.4.1. Streams as Standard Interfaces 205
3.4.2. Higher Order Procedures for Streams 209
- 3.4-3. Streams and Delayed Evaluation 218
3.4.4. Infinitely Long Streams 223
3.4.5. Streams as Signals 229
3.4.6. Using Streams to Model Local State 234
4. Meta-Linguistic Abstraction 239
4.1. The Meta-circular Evaluator 241
4.1.1. The core of the evaluator: EVAL and APPLY 243
4.1-2. Representing Expressions 246
4.1-3. Representing environments 250
4.1.4. Running the Evaluator as a Lisp Program 252
4.1.5. EVAL: Treating Expressions as Programs 254
4.2. Variations on a Scheme 257
4.2.1. Alternative Binding Disciplines .257
4.2.2. Example: Delayed evaluation 261
4.3. Logic Programming 263
4.3.1. Deductive Information Retrieval 266
4.3.2. How the Query System Works 272
4.3.3. The Query Evaluator 278
4.3-4. Is Logic Programming Mathematical Logic? 280
4.4 Implementing the Query System 284
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DRAFT: 31 JULY 1983 .1..
III
4.4.1. Driver Loop and Syntax Processing 284
4.4.2. The Evaluator 285
4.4.3. Pattern Matching and Finding Assertions 287
4.4.4. Rules and Unification 289
4.4.5. Maintaining the Data Base 291
4.4.6. Utility Procedures 294
5. Register Machine' Model of Control 299
5.1. Computing with register machines 300
5. 1. 1. Register transfer machine language 302
5.1.2. Compound submachines 30.4
6.1.3. Sharing in machines 305
5.1.4. Using a stack to implement recursion 308
5.1.5. Problem section: A register machine smulator 313
5.2. The explicit control evaluator 318
5.2.1. Problem section: Performance Analysis of the Evaluator 329
5.3. Storage allocation and garbage collection 332
5.3. 1. Memory as vectors 332
5.3.2. Supporting the illusion of infinite memory 333
5.4. Compilation 338
5.4. 1. Our system 339
5.4.2. Representations 349
5.4.3. An example of compilation 352
5.4.4. Problem section: Compiled Code 355
5.4.5. Problem section: Compiled Lexical Lookup 357
5.5. Summary 358
Appendix 1. Using Environments to Create Packages 359
References 361
Index 365
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iv DRAFT: 31 JULY 1983
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DRAFT: 31 JULY 1983 v
List of Exercises
Chapter 1: Building Abstractions with Procedures
Exercise 1- 22
Exercise 12 23
Exercise 13 23
Exercise 14 23
Exercise 1- 25
Exercise 16 26
Exercise 1-7 26
Exercise 1-8 34
Exercise 19 34
Exercise 1-1 39
Exercise - 40
Exercise 1- 242
Exercise 113 42
Exercise 1-14 42
Exercise 1-15 42
Exercise 116 44
Exercise 117 47
Exercise 1-18 47
Exercise 119 47
Exercise 120 47
Exercise 121 47
Exercise 122 48
Exercise 1-23 48
Exercise 124 51
Exercise 125 51
Exercise 126 51
Exercise 127 62
Exercise 128 55
Exercise 1-29 56
Exercise 130 61
Exercise 31 61
Exercise 132 61
Exercise 133 63
Exercise 134 64
Exercise -35 64
Exercise 136 64
Chapter 2 Building Abstractions with Data
Exercise 21 72
Exercise 22 73
Exercise 23 75
Exercise 24 76
Exercise 25 76
Exercise 26 77
Exercise 27
Exercise 28 77
Exercise 29 77
Exercise 210,77
4(cid:1) -(cid:1) M -- -I I I - -- ---.
VI DRAFT31 JULY 1983 List of Exercises
Exercise 211 78
Exercise 212 78
Exercise 213 78
Exercise 214 79
Exercise 215 79
Exercise 216 83
Exercise 217 83
Exercise 218 83
Exercise 21 83
Exercise 220 84
Exercise 221 84
Exercise 222 5
Exercise 223 87
Exercise 224 87
Exercise 225 87
Exercise 226 90
Exercise 227 91
Exercise 228 91
Exercise 229 95
Exercise 230 95
Exercise 231 97
Exercise 232 97
Exercise 233 98
Exercise 234 99
Exercise 235 101
Exercise 236 102
Exercise 237 107
Exercise 238 108
Exercise 239 108
Exercise 240 108
Exercise 241 108
Exercise 242 109
Exercise 243 120
Exercise 244 121
Exercise 245 122
Exercise 246 122
Exercise 247 124
Exercise 248 125
Exercise 249 126
Exercise 250 130
Exercise 251 130
Exercise 262 130
Exercise 253 131
Exercise 254 131
Exercise 255 131
Exercise 256 131
Exercise 257 136
Exercise 258 136
Exercise 259 136
Exercise 260 136
Exercise 261 137
Exercise 262 138
Exercise 263 138
Exercise 264 139
P.
DRAFT: 31 JULY 1983
vii
Exercise 265 139
Exercise 266 140
Exercise 267 140
Exercise 268 141
Chapter 3 Modularity, Objects, and State
Exercise 31 148
Exercise 32 149
Exercise 33 149
Exercise 34 149
Exercise 35 152
Exercise 36 153
Exercise 37 165
Exercise 38 161
Exercise 39 166
Exercise 310 169
Exercise 311 173
Exercise 312 174
Exercise 313 174
Exercise 314 176
Exercise 315 177
Exercise 316 177
Exercise 317 178
Exercise 318 182
Exercise 319 182
Exercise 320 182
Exercise 321 185
Exercise 322 185
Exercise 323 185
Exercise 324 186
Exercise 325 190
Exercise 326 190
Exercise 327 190
Exercise 328 194
Exercise 329 203
Exercise 330 203
Exercise 331 203
Exercise 332 2T.4
Exercise 333 204
Exercise 34 216
Exercise 335 216
Exercise 336 216
Exercise 337 217
Exercise 338 217
Exercise 339 222
Exercise 340 222,
Exercise 341 226
Exercise 342 227
Exercise 343 227
Exercise 344 227
Exercise 345 228
Exercise 346 228
Exercise 347 228
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Vill DRAFT: 31 JULY 1983 List Of Exercises
Exercise 348 230
Exercise 349 230
Exercise 350 231
Exercise 351 231
Exercise 352 232
Exercise 353 233
Exercise 354 233
Exercise 355 233.
Exercise 356 233
Exercise 357 235
Exercise 358 236
Chapter 4 Meta-Linguistic Abstraction
Exercise 41 244
Exercise 42 249
Exercise 43 249
Exercise 44 249
Exercise 45 252
Exercise 46 252
Exercise 47 253
Exercise 48 256
Exercise 49 260
Exercise 410 260
Exercise 411 260
Exercise 412 260
Exercise 413 262
Exercise 414 262
Exercise 415 262
Exercise 416 262
Exercise 417 268
Exercise 418 269
Exercise 419 270
Exercise 420 271
Exercise 421 271
Exercise 422 272
Exercise 423 282
Exercise 424 282
Exercise 425 283
Exercise 426 283
Exercise 427 296
Exercise 428 297
Exercise 429 297
Exercise 430 297
Chapter 5: Register Machine Model of Contro
Exercise 5-1 312
Exercise 52 313
Exercise 53 313
Exercise 54 318
Exercise -5 318
Exercise 56 318
Exercise 57 330
Exercise 5-8 330
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DRAFT: 31 JULY 1983 Ir.,-!,-, ix
Exercise 59 331
Exercise 10 331
Exercise -1 331
Exercise 6- 12 331
Exercise 513 338
Exercise -14 356
Exercise 15 356
Exercise 5-16 357
Exercise 517 358
Exercise 18 358
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