Mundo Oxidado - A Rusty World

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# Mundo Oxidado

## A Rusty World

### 2017-10-04 - Nardoz Buenos Aires
### Jan-Erik Rediger — [@badboy_](https://twitter.com/badboy_)

???

Buenos Noches

Thanks for coming, I’m here because Seppo knew I was visiting BA and asked me to give a talk.

I will do this mostly in English because my Spanish is limited to one full but important sentence:

Donde esta mi cerveza?

As a German that’s enough to survive

*click*

So who am I?

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## It's me, Jan-Erik

## Traveler

## Software Developer <strike>& Student</strike>

--
 
## Mozilla TechSpeaker

--
 
## Rustacean

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![Rustfest Zurich](media/RFZ-logo.png)

???

I was also a co-organizer of the first two RustFests, the european Rust conference.

The third iteration happened last weekend in Zurich, Switzerland.

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???

Before we get into Rust, I want to know a bit about you

Raise your hands.

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# Developer?

???

Who here writes code for a living?

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# Not a developer?

???

who here does not write code directly, e.g. documentation, project management or something completely different?

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# Your language of choice?

???

Now on to languages.

Backend devs?

Frontend devs?

Fullstack?

Java?

Python/Ruby?

anything I missed?

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# Rust Dev?

???

Who does Rust?

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![](media/rust-logo.png)

???

Good.
So I know there were already talks about rust here.

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background-image: url(media/better-dev-tweet.png)

.footnote[["Rust made me a better C programmer."](https://twitter.com/badboy_/status/820054791397244932)]

???

I was even quoted!

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## Rust

```rust
fn main() {
    let program = "+ + * - /";
    let mut accumulator = 0;

for token in program.chars() {
        match token {
            '+' => accumulator += 1,
            '-' => accumulator -= 1,
            '*' => accumulator *= 2,
            '/' => accumulator /= 2,
            _ => { /* ignore everything else */ }
        }
    }

println!("The program \"{}\" calculates the value {}",
              program, accumulator);
}
```

.footnote[["Rust for Rubyists"](https://fnordig.de/talks/2014/froscon/rust-for-rubyists/#/), FrOSCon, RedFrogConf, 24.08.2014]

???

This is Rust.

It's actually the example I used in my very first rust talk more than 3 years ago

It was also the one used on the website

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> Rust is a systems programming language that runs blazingly fast, prevents segfaults, and guarantees thread safety.

???

Rust itself advertises it by this sentence:

**Rust is a systems programming language that runs blazingly fast, prevents segfaults, and guarantees thread safety.**

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> Rust is a systems programming language that runs blazingly fast, prevents segfaults, and guarantees thread safety.

???

A bit much.

Let's focus on the core aspects.

blazingly fast

prevents segfaults

thread safety

I will tell you how it achieves all of that

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## Historia

* started in 2010 by Graydon Hoare

* Version 1.0 in May 2015

* Current: 1.20\*

* sponsored by Mozilla

.footnote[\* v1.21 on October 12th]

???

Historia. I'm getting good at this Spanish thing, right?

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## Why Rust?

* Memory safety

* "Zero-Cost abstractions"

* FFI for interoperability with C

* low-level where necessary

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> Rust exists to write tools that already exist elsewhere.
> Lucas (<a href="http://twitter.com/moonbeamlabs">@moonbeamlabs</a>)

.footnote[["Nerdkunde 43" (German Podcast)](http://www.nerdkunde.de/45-die-menschliche-moehre)]

???

Another friend put it this way

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## Where Rust?

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![](media/tdo_schauspiel.png)
![](media/rrbone.png)

.footnote[[midioscar](https://github.com/rrbone/midioscar), [Einstein on the Beach](https://www.theaterdo.de/detail/event/einstein-on-the-beach/)]

???

a midi to osc proxy

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## How Rust?

* Open development on [github.com/rust-lang](https://github.com/rust-lang/)

* RFCs for all changes

* Frequent, constant releases (6 weeks)

---

## Core concepts

* Ownership & Borrowing

* Explicitness\*

* Compiler support

* Better tooling

.footnote[\* unless too much]

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## Ownership & Borrowing

.left-column[
### Ownership

* Data has a single owner

* Responsible for resources
]

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### Borrowing

### Either

* multiple immutable borrows

### or

* one mutable borrow
]

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# Ready for some code?

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## Ownership & Borrowing

.left-column[
### Ownership
```rust
fn greet(name: String) {
    println!("¡Hola, {}!", name);
}
```
]

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### Immutable borrowing
```rust
fn greet(name: &String) {
    println!("¡Hola, {}!", name);
}
```

### Mutable borrowing
```rust
fn greet(name: &mut String) {
    name.push_str(", hola!");
}
```
]

.footnote[[Playground Example](https://play.rust-lang.org/?gist=a25652bae5823534267b878e50ac2c6d&version=stable)]

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## Explicitness: Error Handling

.left-column30[
### (Generic) Result
```rust
enum Result<T, E> {
 Ok(T),
 Err(E)
}
```
]

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### Error handling
```rust
fn this_can_fail(succeeds: bool) -> Result<String, String> {
 if succeeds {
 Ok(String::from("Success"))
 } else {
 Err(String::from("Error"))
 }
}

fn main() {
    let outcome = this_can_fail(true);
    println!("{:?}", outcome);
}
```
]

.footnote[[Playground Example](https://play.rust-lang.org/?gist=783ffd3b75f34e3706c2dc75e6e35639&version=stable)]

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## Compiler Support

```rust
fn main() {
    let meetup = "Nardoz";
    println!("{}", metup);
}
```

```rust
$ rustc hello.rs
error[E0425]: cannot find value `metup` in this scope
 --> hello.rs:3:20
  |
3 |     println!("{}", metup);
  |                    ^^^^^ did you mean `meetup`?

error: aborting due to previous error

```

.footnote[[Playground Example](https://play.rust-lang.org/?gist=59afbf3225e84dde01722654418d893a&version=stable)]

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## Compiler Support

```rust
fn borrow_same_field_twice_mut_mut() {
    let mut foo = make_foo();
    let bar1 = &mut foo.bar1;
    let _bar2 = &mut foo.bar1;
    *bar1;
}
```

```rust
$ rustc hello.rs
error[E0499]: cannot borrow `foo.bar1` as mutable more than once at a time
  --> hello.rs:10:22
   |
9  |     let bar1 = &mut foo.bar1;
   |                     -------- first mutable borrow occurs here
10 |     let _bar2 = &mut foo.bar1;
   |                      ^^^^^^^^ second mutable borrow occurs here
11 |     *bar1;
12 | }
   | - first borrow ends here

error: aborting due to previous error
```

.footnote[[Playground Example](https://play.rust-lang.org/?gist=581129bff87d864f17a20cbde0d41809&version=stable)]

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## Tooling: Cargo

* package manager, build system, registry

* <strike>7600</strike> 11600 Crates

* `cargo new` → project setup

* `cargo build` → download deps & build

.footnote[[crates.io](https://crates.io)]

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## More tooling

* RLS → IDE-like support everywhere

* `rustfmt` → one format to rule them all

* `clippy` → a bunch of lints

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# Demo Time\*

.footnote[\* requires Rust Nightly…]

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## #rust IRC channel search index

* index 3 years of IRC chatter

* web frontend for users

* search by nick and messages

.footnote[(for lack of own projects to show I built on top of others!)]

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![](media/search-frontend.png)

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## Demo Time - Stats

* one night of hacking

* ~350 lines of code

* 162M input data (july 2014 - october 2017)

* 185M index (with all data)

* 16s indexing time

* blazingly fast web frontend

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## Demo Time - Resources

* [Tantivy](https://github.com/tantivy-search/tantivy]): full-text search engine

* [Rocket](https://rocket.rs/): web framework

* [regex](https://github.com/rust-lang/regex) : one of the fastest regex engines

* [Serde](https://serde.rs/): <strike>a</strike> **the** framework for serializing and deserializing

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## más óxido

* [rust-lang.org](https://www.rust-lang.org/)

* [community.rs/resources](https://community.rs/)

* [play.rust-lang.org](https://play.rust-lang.org/)

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# ¡Muchas gracias!

## [@badboy_](https://twitter.com/badboy_) / janerik@fnordig.de