The OCaml Handbook

A Complete Guide from First Program to Production Systems

Introduction: Why OCaml Matters

Chapter 1: Welcome to OCaml

1. A Brief History of ML and OCaml
2. Why OCaml Matters Today
3. Installing OCaml and Your First Program
4. The REPL: Interactive Exploration
5. How This Book Is Structured
6. Chapter Summary
7. Exercises
8. Key Takeaways
9. References for Further Reading

Chapter 2: Values, Types, and Expressions

1. Everything Is an Expression
2. Basic Types: Integers, Floats, Booleans, Characters
3. Type Inference: Let the Compiler Help You
4. Functions as First-Class Values
5. Let Bindings and Scoping Rules
6. Recursive Functions
7. Common Pitfalls
8. Chapter Summary
9. Exercises
10. Key Takeaways
11. References for Further Reading

Chapter 3: Pattern Matching–The Heart of OCaml

1. The Match Expression
2. Patterns for Every Type
3. Wildcards and Guards
4. Exhaustiveness Checking
5. Pattern Matching in Let Bindings
6. Real-World Examples and Exercises
7. Chapter Summary
8. Exercises
9. Key Takeaways
10. References for Further Reading

Chapter 4: Variants and Algebraic Data Types

1. Sum Types and the Variant Construct
2. Tagged Unions vs Enums
3. Recursive Variants for Trees and Lists
4. Polymorphic Variants
5. Sealed Types and Private Constructors
6. Design Patterns with Variants
7. Chapter Summary
8. Exercises
9. Key Takeaways
10. References for Further Reading

Chapter 5: Records and Structured Data

1. Defining Record Types
2. Field Access and Update
3. Polymorphic Records
4. Labels vs Fields
5. Records in Practice
6. Exercises
7. Chapter Summary
8. Key Takeaways
9. References for Further Reading

Chapter 6: Higher-Order Functions and the Standard Library

1. Functions That Take Functions
2. The List Module: Map, Filter, Fold
3. Partial Application and Currying
4. Function Composition
5. Common Combinators and Patterns
6. The Pipeline Style
7. Exercises
8. Chapter Summary
9. Key Takeaways
10. References for Further Reading

Chapter 7: Modules–OCaml’s Type System for Code Organization

1. What Is a Module?
2. Module Types and Signatures
3. Functors: Modules That Take Modules
4. First-Class Modules
5. Sealing and Abstraction
6. Designing Module Interfaces
7. Exercises
8. Chapter Summary
9. Key Takeaways
10. References for Further Reading

Chapter 8: Polymorphism and Generic Programming

1. Parametric Polymorphism
2. Constraints and Bounds
3. First-Class Modules as Generics
4. Module Types with Inclusion
5. Advanced Polymorphism Patterns
6. Exercises
7. Chapter Summary
8. Key Takeaways
9. References for Further Reading

Chapter 9: Exceptions and Error Handling

1. Raising and Catching Exceptions
2. Custom Exception Types
3. Result Types vs Exceptions
4. Best Practices and Anti-Patterns
5. Exercises
6. Chapter Summary
7. Key Takeaways
8. References for Further Reading

Chapter 10: Mutable State and References

1. Why Mutation in a Functional Language?
2. References and Arrays
3. In-Place Updates and Side Effects
4. Managing Mutability Responsibly
5. Imperative vs Functional Styles
6. Exercises
7. Chapter Summary
8. Key Takeaways
9. References for Further Reading

Chapter 11: Objects and the Object System

1. Classes and Objects
2. Inheritance and Method Overriding
3. Interfaces and Type Constraints
4. When to Use Objects vs Modules
5. Exercises
6. Chapter Summary
7. Key Takeaways
8. References for Further Reading

Chapter 12: Concurrency and Parallelism

1. Threads and Mutexes
2. Message Passing with Channels
3. The Global Lock and Its Implications
4. Multicore OCaml: The Road Ahead
5. Concurrent Data Structures
6. Exercises
7. Chapter Summary
8. Key Takeaways
9. References for Further Reading

Chapter 13: Testing, Debugging, and Build Systems

1. OPAM: Package Management
2. Dune: The Build System
3. Unit Testing with Alcotest
4. Property-Based Testing with QCheck
5. Debugging Techniques and Tools
6. Exercises
7. Chapter Summary
8. Key Takeaways
9. References for Further Reading

Chapter 14: Performance and Optimization

1. Understanding the Runtime
2. Compiler Flags and Optimization Levels
3. Flame Graphs and Profiling
4. Memory Management and Garbage Collection
5. Writing Tight Code
6. Benchmarking Strategies
7. Exercises
8. Chapter Summary
9. Key Takeaways
10. References for Further Reading

Chapter 15: Foreign Function Interfaces and Interop

1. The C Foreign Function Interface (FFI)
2. Stubs and Bindings
3. Calling OCaml from C
4. Performance Considerations
5. Modern Tooling for FFI
6. Exercises
7. Chapter Summary
8. Key Takeaways
9. References for Further Reading

Chapter 16: Metaprogramming and Compiler Internals

1. PPX Rewriters
2. The ppxlib Ecosystem
3. AST Manipulation
4. The Compiler Pipeline
5. Parsing and Lexing with Menhir and Angstrom
6. Building Domain-Specific Languages
7. Exercises
8. Chapter Summary
9. Key Takeaways
10. References for Further Reading

Chapter 17: Real-World Software Engineering

1. Project Structure and Organization
2. Common Design Patterns in OCaml
3. The Ecosystem: Key Libraries
4. Documentation with Odoc
5. CI/CD for OCaml Projects
6. Best Practices Checklist
7. Exercises
8. Chapter Summary
9. Key Takeaways
10. References for Further Reading

Chapter 18: Advanced Applications–Parsers, Compilers, and DSLs

1. Parser Combinators
2. Building a Compiler with OCaml
3. Domain-Specific Languages
4. Real-World Examples
5. Exercises
6. Chapter Summary
7. Key Takeaways
8. References for Further Reading

Chapter 19: Systems Programming and Web Development

1. Systems Programming with OCaml
2. The Mirage OS Project
3. Web Development with Dream and Cohttp
4. Server-Side Applications
5. Production Deployment Patterns
6. Exercises
7. Chapter Summary
8. Key Takeaways
9. References for Further Reading

Chapter 20: Capstone–Building a Production Application

1. Project Design and Architecture
2. Implementation Walkthrough
3. Testing Strategy
4. Performance Tuning
5. Deployment
6. Lessons Learned
7. Chapter Summary
8. Key Takeaways
9. References for Further Reading

Conclusion: Your OCaml Journey Ahead

References