presentation-rust-introduction/rust-intro.org

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#+TITLE: \includesvg[height=.25\textheight]{img/rust-logo-blk}\newline An introduction to Rust
#+AUTHOR: \href{mailto:finga@onders.org}{finga}
#+EMAIL: finga@onders.org
#+SUBTITLE: A language empowering everyone to build reliable and efficient software.
#+DATE: \today
#+DESCRIPTION: An introduction into Rust and its ecosystems.
#+LANGUAGE: en
#+KEYWORDS: rust programming
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* Rust
** Abstract
   #+BEGIN_CENTER
   #+LaTeX:\includegraphics[width = 0.5\textwidth]{img/Bruine_roest_op_tarwe_(Puccinia_recondita_f.sp._tritici_on_Triticum_aestivum).jpg}
   [fn:1]
   #+END_CENTER

*** Rust, the language
    - First appearance 2010
    - Memory safe without gcing, optional reference counting
    - Ownership, lifetimes, traits, functional paradigms
    - Variables are immutable by default and can be shadowed
    - Performance of idiomatic Rust is comparable to the performance
      of idiomatic C++
    - A well designed language and ecosystem

** Strengths and Weaknesses[fn:2]
*** Things Rust does measurably really well (Strengths)
    - Compiled code [[https://benchmarksgame-team.pages.debian.net/benchmarksgame/which-programs-are-fastest.html][about same performance as C / C++]], and excellent
      [[https://dl.acm.org/doi/10.1145/3136014.3136031][memory and energy efficiency]].
    - Can [[https://www.chromium.org/Home/chromium-security/memory-safety][avoid 70% of all safety issues]] present in C / C++, and most
      memory issues.
    - Strong type system prevents [[https://doc.rust-lang.org/nomicon/races.html][data races]], brings [[https://blog.rust-lang.org/2015/04/10/Fearless-Concurrency.html]['fearless
      concurrency']] (amongst others).
    - Seamless C interop, and [[https://doc.rust-lang.org/rustc/platform-support.html][dozens of supported platforms]] (based on
      LLVM).[fn:4]
    - [[https://insights.stackoverflow.com/survey/2021#technology-most-loved-dreaded-and-wanted]["Most loved language"]] for 6 years in a row.
    - Modern tooling: ~cargo~ (builds just work), ~clippy~ (450+ code
      quality lints), ~rustup~ (easy toolchain management).

** Strengths and Weaknesses[fn:3]
*** Points you might run into (Weaknesses)
    - Steep learning curve[fn:5] compiler enforcing (esp. memory)
      rules that would be "best practices" elsewhere.
    - Missing Rust-native libs in some domains, target platforms
      (esp. embedded), IDE features.[fn:5]
    - Longer compile times than "similar" code in other
      languages.[fn:5][fn:6]
    - No formal language specification, can prevent legal use in some
      domains (aviation, medical, ...).[fn:7]
    - Careless (use of ~unsafe~ in) libraries can secretly break
      safety guarantees.

** Problems and security Rust tries to conquer
   #+BEGIN_CENTER
   #+LaTeX:\includegraphics[width = 0.8\textwidth]{img/compiler_complaint.png}
   [fn:8]
   #+END_CENTER

   - Dangling pointers / memory safety
   - Iterator invalidation
   - Thread safety / concurreny
   - Segfaults
   - Error handling
   - Zero-cost abstractions

** Where to start?
*** First Steps
    - [[https://tourofrust.com/TOC_en.html][Tour of Rust]]
    - [[https://doc.rust-lang.org/book/][The Rust Book]] (~$ rustup docs --book~)
    - [[https://dhghomon.github.io/easy_rust/Chapter_1.html][Rust in Easy English]]
    - [[https://doc.rust-lang.org/rust-by-example/][Rust by Example]] (~$ rustup docs --rust-by-example~)
    - [[https://doc.rust-lang.org/std/][The Rust Standard Library]] (~$ rustup docs --std~)
    - [[https://doc.rust-lang.org/nomicon/][The Rustonomicon]]: The Art of unsafe Rust (~$ rustup docs
      --nomicon~)
    - Use '~$ rustup help docs~' to get an overview

*** Other helpful sites
    - [[https://cheats.rs][cheats.rs]]
    - [[https://programming-idioms.org/cheatsheet/Rust][programming-idioms.org]]

** Where to find help and stay up to date
*** Chat (Discord)
    - [[https://discord.gg/rust-lang][The Rust Programming Language]]
    - [[https://discord.com/invite/tcbkpyQ][The Rust Programming Language Community Server]]

*** Boards/Blogs
    - [[https://blog.rust-lang.org/][Rust Blog]]
    - [[https://www.reddit.com/r/rust][r/rust]]
    - [[https://this-week-in-rust.org/][This Week in Rust]]

** Language
   - Semicolons have meaning
   - Mutability
   - Shadowing
   - Functional paradigms

** Mutability and shadowing
*** Immutable variable
    #+BEGIN_SRC rust
    let foo = 5;
    #+END_SRC

*** Mutable variable
    #+BEGIN_SRC rust
    let mut bar = 5;
    bar = 6;
    #+END_SRC

*** Shadowing
    #+BEGIN_SRC rust
    let baz = 5;
    let baz = baz + 3;
    #+END_SRC

** Type aliases

** Tuple structs
*** Definition of a tuple struct
     #+BEGIN_SRC rust
     struct Rectangle(usize, usize);
     #+END_SRC

*** Instantiation of a tuple struct
    #+BEGIN_SRC rust
    let rect = Rectangle(3, 5);
    #+END_SRC

*** Access of a tuple struct's field
    #+BEGIN_SRC rust
    rect.0;
    rect.1;
    #+END_SRC

** Structs
   - Direct access vs. getter and setter
   - ~Something::new(item)~ and ~Something::default()~

*** Definition of a struct
     #+BEGIN_SRC rust
     struct Something {
         id: usize,
         item: String,
     }
     #+END_SRC

** Error related types
   - Heavy use of ~Option<T>~ and ~Result<T, E>~

*** Option
    #+BEGIN_SRC rust
    pub enum Option<T> {
        None,
        Some(T),
    }
    #+END_SRC

*** Result
    #+BEGIN_SRC rust
    pub enum Result<T, E> {
        Ok(T),
        Err(E),
    }
    #+END_SRC

** Error handling

*** Unrecoverable errors \rightarrow panics
    #+BEGIN_SRC rust
    fn get_data() -> Data {
        ...
        panic!("Cannot get data");
    }
    #+END_SRC

*** Recoverable error with anyhow
    #+BEGIN_SRC rust
    fn get_data() -> Result<Data> {
        ...
        Ok(data) // return is only used for "early" returns
    }
    ...
        let data = get_data()?;
    ...
    #+END_SRC

** Use functional language features
   - ~vec![1, 2, 3].iter()~
   - ~vec![1, 2, 3].iter().sum()~
   - ~vec![1, 2, 3].iter().map(|x| x + 1).collect()~
   - ~foo.into_iter().filter(|i| i.bar == 0).collect()~
   - ~Iterator~ trait

** Control structures
   - ~if~, ~if let~, ~match~
   - ~loop~, ~for~, ~map()~

** Tests
   - Use ~assert!()~ family
   - Unit tests
     - Put them into a test module
     - Annotate the test module with ~#[cfg(test)]~
     - Annotate the tests with ~#[test]~
   - Documentation testing
   - Integration testing
     - Integration tests are put into the ~src/tests/~ directory

** Documentation
   - Documentation comments: ~///~
   - Markdown notation
   - ~cargo doc~ runns rustdoc which generates html docs
   - ~cargo doc --open~ runs rustdoc and opens the result in a browser
   - rustdoc documentation: https://doc.rust-lang.org/beta/rustdoc/index.html

** FFI (Foreign Function Interface)

* Cargo
** Cargo
   #+BEGIN_CENTER
   \Huge *Cargo*
   #+END_CENTER

   #+ATTR_LaTeX: :height 0.4\textwidth
   [[./img/cargo.png]]

** What is it?
   - Package manager
   - Cargo calls ~rustc~, the Rust compiler
   - Build tool
   - A Cargo project contains at least one crate

** Hello, World
   Executing ~`cargo new foobar`~ creates a new project...

*** foobar/Cargo.toml
    #+BEGIN_SRC toml
    [package]
    name = "foo"
    version = "0.1.0"
    authors = ["finga <finga@onders.org>"]
    edition = "2018"
    #+END_SRC
    \tiny
    #+BEGIN_SRC toml
    # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
    #+END_SRC
    \normalsize
    #+BEGIN_SRC toml
    [dependencies]
    #+END_SRC

*** foobar/src/main.rs
    #+BEGIN_SRC rust
    fn main() {
        println!("Hello, world!");
    }
    #+END_SRC

** Docs
   - [[https://doc.rust-lang.org/cargo/index.html][The Cargo Book]] (~$ rustup docs --cargo~)

** Cargo commands/plugins
*** What I typically use
    - ~audit~: Audit ~Cargo.lock~ for security vulnerabilities.
    - ~bloat~: Identify which dependency adds how much bloat.
    - ~checkmate~: Run a list of checks (~check~, ~format~, ~build~,
      ~test~, ~doc~, ~audit~).
    - ~clippy~: Linter and static code analysis.
    - ~deb~: Automatically create a Debian package.
    - ~flamegraph~: Generate flamegraphs about anything.
    - ~fmt~: Format Rust code according to style guidelines.
    - ~install-update~: Keep all your Cargo commands up to date.

*** @@comment: comment@@
    Cargo downloads your Rust package's dependencies, compiles your
    package, makes distributable packages, and uploads them to
    [[https://crates.io][crates.io]], the Rust community's package registry.

** The Rust (package) registry

*** Official registry
    [[https://crates.io][crates.io]]

*** Unofficial [[https://crates.io][~crates.io~]] frontend
    [[https://lib.rs][lib.rs]] same but different..

** Docs
   - The [[https://doc.rust-lang.org/cargo/][Cargo Book]].

* Setup
** Install the Rust-Toolchain
*** Install Rust
    From [[https://rustup.rs][rustup.rs]]:
    ~$ curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh~

*** Rustup: The Rust toolchain installer
    - Check for new versions: ~$ rustup check~
    - Update the toolchain: ~$ rustup update~
    - Update rustup itself: ~$ rustup self update~
    - Install Rust nightly (daily builds):
      ~$ rustup toolchain install nightly~
    - Activate nightly globally: ~$ rustup default nightly~
    - Activate nightly locally (in current dir):
      ~$ rustup override set nightly~

** Handle the Rust toolchain with ~rustup~

*** Install the Rust toolchain ([[https://rustup.rs][~rustup.rs~]])
    #+BEGIN_SRC sh
    $ curl --proto '=https' --tlsv1.2 -sSf \
      https://sh.rustup.rs | sh
    #+END_SRC

*** Update ~rustup~
     #+BEGIN_SRC sh
     $ rustup self update
     #+END_SRC

*** Check for updates for installed toolchains
     #+BEGIN_SRC sh
     $ rustup check
     #+END_SRC

*** Update toolchains if outdated
     #+BEGIN_SRC sh
     $ rustup update
     #+END_SRC

* IDE support
** Are we IDE yet?[fn:9]
   \tiny
|                     | \rotatebox{90}{Syntax highlightning (.rs)} | \rotatebox{90}{Syntax highlightning (.toml)} | \rotatebox{90}{Snippets} | \rotatebox{90}{Code Completion} | \rotatebox{90}{Linting} | \rotatebox{90}{Code Formatting} | \rotatebox{90}{Go-to Definiton} | \rotatebox{90}{Debugging} | \rotatebox{90}{Documentation Tooltips} |
|---------------------+--------------------------------------------+----------------------------------------------+--------------------------+---------------------------------+-------------------------+---------------------------------+---------------------------------+---------------------------+----------------------------------------|
| Atom                | [X]                                        | [X]                                          | [X]                      | [X]                             | [X]                     | [X]                             | [X]                             |                           | [X]                                    |
| Emacs               | [X]                                        | [X]                                          | [X]                      | [X]                             | [X]                     | [X]                             | [X]                             |                           | [X]                                    |
| Sublime             | [X]                                        | [X]                                          | [X]                      | [X]                             | [X]                     | [X]                             | [X]                             |                           |                                        |
| Vim/Neovim          | [X]                                        | [X]                                          | [X]                      | [X]                             | [X]                     | [X]                             | [X]                             |                           | [X]                                    |
| VS Code             | [X]                                        | [X]                                          | [X]                      | [X]                             | [X]                     | [X]                             | [X]                             | [X]                       | [X]                                    |
| BBedit              | [X]                                        | [X]                                          | [X]                      |                                 |                         | [X]                             | [X]                             |                           |                                        |
| Geany               | [X]                                        |                                              |                          |                                 |                         |                                 |                                 |                           |                                        |
| gedit               | [X]                                        |                                              |                          | [X]                             |                         |                                 | [X]                             |                           |                                        |
| Kakoune             | [X]                                        | [X]                                          | [X]                      | [X]                             | [X]                     | [X]                             | [X]                             |                           | [X]                                    |
| Kate                | [X]                                        | [X]                                          |                          | [X]                             | [X]                     | [X]                             | [X]                             |                           |                                        |
| Micro               | [X]                                        | [X]                                          |                          |                                 | [X]                     | [X]                             |                                 |                           |                                        |
| Midnight Commander  | [X]                                        |                                              |                          |                                 |                         |                                 |                                 |                           |                                        |
| Textadept           | [X]                                        | [X]                                          | [X]                      | [X]                             | [X]                     |                                 | [X]                             |                           |                                        |
|---------------------+--------------------------------------------+----------------------------------------------+--------------------------+---------------------------------+-------------------------+---------------------------------+---------------------------------+---------------------------+----------------------------------------|
| Eclipse             | [X]                                        |                                              | [X]                      | [X]                             | [X]                     | [X]                             | [X]                             | [X]                       | [X]                                    |
| IntelliJ-based IDEs | [X]                                        | [X]                                          | [X]                      | [X]                             | [X]                     | [X]                             | [X]                             | [X]                       | [X]                                    |
| Visual Studio       | [X]                                        |                                              |                          | [X]                             |                         |                                 | [X]                             | [X]                       |                                        |
| GNOME Builder       | [X]                                        |                                              | [X]                      | [X]                             | [X]                     | [X]                             | [X]                             |                           |                                        |
| Ride                | [X]                                        |                                              |                          |                                 |                         |                                 |                                 |                           |                                        |

* Common Crates
  - [[https://crates.io][crates.io]]/[[https://lib.rs][lib.rs]]
  - [[https://github.com/rust-unofficial/awesome-rust][Awesome Rust]]

  - clap (command line argument parser)
  - env_logger, log
  - dotenv
  - serde
  - lazy_static, once_cell (globality, singleton, lazy initialization)
  - nom
  - tokio

** Databases
   - sqlx
   - diesel

** WebDev
   [[https://www.arewewebyet.org/][Are we web yet]]

   - Actix
   - Hyper
   - Rocket
   - reqwest

** Embedded
   [[https://niclashoyer.github.io/areweembeddedyet/][Are we embedded yet]]
   [[https://niclashoyer.github.io/areweembeddedyet/][Awesome Embedded Rust]]
   [[https://docs.rust-embedded.org/embedonomicon/][Embedonomicon]]

   - avr
   - stm
   - msp430
   - esp32

* Footnotes
[fn:1] [[https://commons.wikimedia.org/wiki/File:Bruine_roest_op_tarwe_(Puccinia_recondita_f.sp._tritici_on_Triticum_aestivum).jpg][Wikimedia]]
[fn:2] Copied list from: [[https://cheats.rs/#tab-hello-3][cheats.rs]].
[fn:3] Copied list from: [[https://cheats.rs/#tab-hello-4][cheats.rs]].
[fn:4] Work on GCC: [[https://rust-gcc.github.io/][rust-gcc]] and [[https://news.ycombinator.com/item?id=27775544][gcc rust backend]].
[fn:5] [[https://blog.rust-lang.org/2020/04/17/Rust-survey-2019.html#why-not-use-rust][Rust survey]]
[fn:6] [[https://news.ycombinator.com/item?id=23538220][The Rust compiler isn't slow; we are]]
[fn:7] [[https://people.mpi-sws.org/%7Ejung/thesis.html][Understanding and Evolving the Rust Programming Language]]
[fn:8] https://xkcd.com/371/
[fn:9] [[https://areweideyet.com/][areweideyet.com]]