chapter 2
https://doc.rust-lang.org/book/ch02-00-guessing-game-tutorial.html

include packages:
  using std::io;

print is a macro:
  println!("text");

make a new mutable string:
  let mut guess = String::new();
  // new is a function of the string type.
  // an "associated function"

& is a reference

result is an enumeration
it's variants are "Ok" and "Err"


There are a set of "items" defined before importing anything. This is called the "prelude".


chapter 1
https://doc.rust-lang.org/book/ch01-00-getting-started.html

linux:
  curl --proto '=https' --tlsv1.2 https://sh.rustup.rs -sSf | sh

update:
  rustup update

docs:
  rustup doc

compiler is `rustc`

cargo --version

toml = toms obvious minimal language

new project:
  cargo new $project_name --vcs=none

$project_dir/
$project_dir/Cargo.toml
$project_dir/src/main.rs
$project_dir/target/debug/$project_bin

build:
  cargo build

run:
  cargo run

don't compile, just check:
  cargo check

don't add debug symbols:
  cargo build --release