Module¶

https://www.reddit.com/r/rust/comments/y3p5hx/how_can_i_have_multi_level_module_nesting/

src/
    main.rs
    foo.rs
    foo/
        bar.rs
        bar/
            baz.rs

• main.rs must contain a mod foo; line

• foo.rs or foo/mod.rs must contain a mod bar; line

• foo/bar.rs or foo/bar/mod.rs must contain a mod baz; line

When rust encounters mod name;, it goes and finds name.rs or name/mod.rs and uses its contents as the module at that site.