Module -> Crate -> Package

Binary Crate
Library Crate (tip: should contain the module tree, binary crate should be a client to the lib)

Package: n binary crates, 1 library crate
`src/main.rs` package exports binary crate of package name
`src/bin/*.rs` multiple binary crates
`src/lib.rs` package exports library crate of package name

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Absolute import path start with `crate::` etc.
Relative import path start with `self::` , `super::`, or an identifier in the current mod.
`super` starts rel path from the parent module.
child scope can access everything in parent scope even privates.

`use` to create a shortcut to crates **only** in the **current** scope. 

It's idiomatic when calling a function to import its parent module so it's clear that the function call is not to a local function. For importing structs and enums and such it's idiomatic to import them all the way (unless its name collides ofc).

`use .. as name` is also possible.

`pub use ..` to re-export it so external callers can also reference it shortly, exposing a different structure to callers than the internal package actually is.

Nesting `use` stmts: `use std::{cmp::Ordering, io};` 
or `use std::io::{self, Write};` instead of `std::io;` and `std::io::Write;`.

Glob: `use std::collections::*;`

`pub mod blaat;` -> `src/blaat.rs` -> `pub mod henk;` -> `src/blaat/henk.rs`.
old-style: `src/blaat/mod.rs` -> `src/blaat/henk/mod.rs` (many mod.rs files)

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Standard stuff:
- cargo build
- cargo update
- cargo run

Cool tidbit:
- cargo doc --open