Interior Mutability, Smart Pointers, and Tree Structures in Rust

When writing system-level code or complex data structures like trees and graphs in Rust, one challenge quickly becomes apparent: how do you share and mutate data across many parts of a program without sacrificing memory safety? Rust’s ownership system doesn’t allow multiple &mut references or shared ownership by default. But the standard library offers powerful tools to overcome this — while maintaining safety guarantees. In this post, we explore some of Rust’s most important tools for working with shared, recursive, and mutable data structures: Box Rc / Arc RefCell / Mutex Weak We use a tree structure as our running example and discuss real-world system programming, GUIs, and interpreters.

Apr 26, 2025 - 00:56

Interior Mutability, Smart Pointers, and Tree Structures in Rust

When writing system-level code or complex data structures like trees and graphs in Rust, one challenge quickly becomes apparent:

how do you share and mutate data across many parts of a program without sacrificing memory safety?

Rust’s ownership system doesn’t allow multiple &mut references or shared ownership by default.

But the standard library offers powerful tools to overcome this — while maintaining safety guarantees.

In this post, we explore some of Rust’s most important tools for working with shared, recursive, and mutable data structures:

Box
Rc / Arc
RefCell / Mutex
Weak

We use a tree structure as our running example and discuss real-world system programming, GUIs, and interpreters.