Introduction

Welcome to libr0 - a hands-on journey through Rust's standard library types.

What is libr0?

libr0 is an educational project that reimplements Rust's core standard library types from scratch. By building types like Option, Box, Vec, and Rc yourself, you'll develop a deep understanding of:

• Memory management and allocation
• Smart pointers and ownership patterns
• Interior mutability with Cell and RefCell
• Reference counting and weak references

Who is this for?

This book is designed for developers who:

• Understand basic Rust syntax and ownership rules
• Want to understand how Rust's types work under the hood
• Learn best by building and experimenting with code
• Are curious about memory layout and low-level implementation details

How to use this book

Each chapter covers one type in depth:

1. What problem does it solve? - Understanding the motivation
2. How does it work? - Implementation details with memory diagrams
3. Build it yourself - Runnable examples and exercises
4. Common patterns - Real-world usage scenarios

All implementations use the suffix 0 (e.g., Option0<T>, Vec0<T>) to distinguish them from stdlib types, allowing side-by-side comparison.

Running the code

The complete source code is available at github.com/arinal/libr0. You can:

# Run all tests
cargo test

# Run a specific chapter's examples
cargo run --example option
cargo run --example vec
cargo run --example rc

Ready to dive in?

Start with Chapter 1: Option to begin your journey.