Stage 10.2: Modules

Every Rust program or library is a crate.

Every crate is made of a hierarchy of modules.

Every crate has a root module.

A module can hold global variables, functions, structs, traits or even other modules!

In Rust there is not a 1 to 1 mapping of files to the module tree hierarchy. We must build the module tree explicitly by hand in our code.

Further information:

• https://doc.rust-lang.org/book/ch07-01-packages-and-crates.html
• https://doc.rust-lang.org/book/ch07-02-defining-modules-to-control-scope-and-privacy.html