BillCruise/SICP

SICP

Scheme solutions to exercises in Structure and Interpretation of Computer Programs.

You can find long-form explanations to many of these solutions on my blog at The SICP Challenge.

Chapter 1: Building Abstractions with Procedures

1.1 The Elements of Programming

• 1.1.1 Expressions
• 1.1.2 Naming and the Environment
• 1.1.3 Evaluating Combinations
• 1.1.4 Compound Procedures
• 1.1.5 The Substitution Model for Procedure Application
• 1.1.6 Conditional Expressions and Predicates
• 1.1.7 Example: Square Roots by Newton's Method
• 1.1.8 Procedures as Black-Box Abstractions

1.2 Procedures and the Processes They Generate

• 1.2.1 Linear Recursion and Iteration
• 1.2.2 Tree Recursion
• 1.2.3 Orders of Growth
• 1.2.4 Exponentiation
• 1.2.5 Greatest Common Divisors
• 1.2.6 Example: Testing for Primality

1.3 Formulating Abstractions with Higher-Order Procedures

• 1.3.1 Procedures as Arguments
• 1.3.2 Constructing Procedures Using Lambda
• 1.3.3 Procedures as General Methods
• 1.3.4 Procedures as Returned Values

Chapter 2: Building Abstractions with Data

2.1 Introduction to Data Abstraction

• 2.1.1 Example: Arithmetic Operations for Rational Numbers
• 2.1.2 Abstraction Barriers
• 2.1.3 What Is Meant by Data?
• 2.1.4 Extended Exercise: Interval Arithmetic

2.2 Hierarchical Data and the Closure Property

• 2.2.1 Representing Sequences
• 2.2.2 Hierarchical Structures
• 2.2.3 Sequences as Conventional Interfaces
• 2.2.4 Example: A Picture Language

2.3 Symbolic Data

• 2.3.1 Quotation
• 2.3.2 Example: Symbolic Differentiation
• 2.3.3 Example: Representing Sets
• 2.3.4 Example: Huffman Encoding Trees

2.4 Multiple Representations for Abstract Data

• 2.4.1 Representations for Complex Numbers
• 2.4.2 Tagged data
• 2.4.3 Data-Directed Programming and Additivity

2.5 Systems with Generic Operations

• 2.5.1 Generic Arithmetic Operations
• 2.5.2 Combining Data of Different Types
• 2.5.3 Example: Symbolic Algebra

Chapter 3: Modularity, Objects, and State

3.1 Assignment and Local State

• 3.1.1 Local State Variables
• 3.1.2 The Benefits of Introducing Assignment
• 3.1.3 The Costs of Introducing Assignment

3.2 The Environment Model of Evaluation

• 3.2.1 The Rules for Evaluation
• 3.2.2 Applying Simple Procedures
• 3.3.3 Frames as the Repository of Local State
• 3.3.4 Internal Definitions

3.3 Modeling with Mutable Data

• 3.3.1 Mutable List Structure
• 3.3.2 Representing Queues
• 3.3.3 Representing Tables
• 3.3.4 A Simulator for Digital Circuits
• 3.3.5 Propagation of Constraints

3.4 Concurrency: Time Is of the Essence

• 3.4.1 The Nature of Time in Concurrent Systems
• 3.4.2 Mechanisms for Controlling Concurrency

3.5 Streams

• 3.5.1 Streams Are Delayed Lists
• 3.5.2 Infinite Streams
• 3.5.3 Exploiting the Stream Paradigm
• 3.5.4 Streams and Delayed Evaluation
• 3.5.5 Modularity of Functional Programs and Modularity of Objects

Chapter 4: Metalinguistic Abstraction

4.1 The Metacircular Evaluator

• 4.1.1 The Core of the Evaluator
• 4.1.2 Representing Expressions
• 4.1.3 Evaluator Data Structures
• 4.1.4 Running the Evaluator as a Program
• 4.1.5 Data as Programs
• 4.1.6 Internal Definitions
• 4.1.7 Separating Syntactic Analysis from Execution

4.2 Variations on a Scheme -- Lazy Evaluation

• 4.2.1 Normal Order and Applicative Order
• 4.2.2 An Interpreter with Lazy Evaluation
• 4.2.3 Streams as Lazy Lists

4.3 Variations on a Scheme -- Nondeterministic Computing

• 4.3.1 Amb and Search
• 4.3.2 Examples of Nondeterministic Programs
• 4.3.3 Implementing the Amb Evaluator

4.4 Logic Programming

• 4.4.1 Deductive Information Retrieval
• 4.4.2 How the Query System Works
• 4.4.3 Is Logic Programming Mathematical Logic?
• 4.4.4 Implementing the Query System

Chapter 5: Computing with Register Machines

5.1 Designing Register Machines

• 5.1.1 A Language for Describing Register Machines
• 5.1.2 Abstraction in Machine Design
• 5.1.3 Subroutines
• 5.1.4 Using a Stack to Implement Recursion
• 5.1.5 Instruction Summary

5.2 A Register-Machine Simulator

• 5.2.1 The Machine Model
• 5.2.2 The Assembler
• 5.2.3 Generating Execution Procedures for Instructions
• 5.2.4 Monitoring Machine Performance

5.3 Storage Allocation and Garbage Collection

• 5.3.1 Memory as Vectors
• 5.3.2 Maintaining the Illusion of Infinite Memory

5.4 The Explicit-Control Evaluator

• 5.4.1 The Core of the Explicit-Control Evaluator
• 5.4.2 Sequence Evaluation and Tail Recursion
• 5.4.3 Conditionals, Assignments, and Definitions
• 5.4.4 Running the Evaluator

5.5 Compilation

• 5.5.1 Structure of the Compiler
• 5.5.2 Compiling Expressions
• 5.5.3 Compiling Combinations
• 5.5.4 Combining Instruction Sequences
• 5.5.5 An Example of Compiled Code
• 5.5.6 Lexical Addressing
• 5.5.7 Interfacing Compiled Code to the Evaluator