Rust

https://doc.rust-lang.org/book/

Module

It's dangerous to go alone, pub mod use this.rs

When you use mod in your crate root (src/main.rs), it references a file in the same directory (i.e. src/<name>.rs).

When you use mod in a non-root file (like src/joke.rs), it references a file in a directory with that name (i.e. src/joke/<name>.rs).

Putting a mod.rs file in the directory you want to expose

https://tonydeng.github.io/2019/10/28/rust-mod/