Rust Programming Cookbook

Shared ownership

Ownership and borrowing are fundamental concepts in Rust; they are the reason no runtime garbage collection is required. As a quick primer: how do they work? In short: scopes. Rust (and many other languages) use (nested) scopes to determine the validity of a variable, so it cannot be used outside of the scope (like a function). In Rust, these scopes own their variables, so they will be gone after the scope finishes. In order for the program to move around values, it can transfer ownership to a nested scope or return it to the parent scope.

For temporary transfers (and multiple viewers), Rust has borrowing, which creates a reference back to the owned value. However, these references are less powerful, and sometimes more complex ...