Rust in ten slides

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# Getting started with Rust

### This presentation will help you get Rust installed, demonstrate some neat tools, and show you "hello world"

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## Installing Rust

The best way to install Rust is with [rustup](https://www.rustup.rs/), a Rust
version manager. To install it type:

```bash
$ curl https://sh.rustup.rs -sSf | sh
```

To keep your rust up-to-date with the latest release of rust,
type:

```bash
$ rustup update
```

To check which version of Rust you have type:

```bash
$ rustc --version
```

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## cargo

Cargo is a tool that helps you develop Rust programs. It does several things:

- Runs tasks: `cargo build` (compile your app), `cargo test` (test your app), `cargo run` (run your app)
- Start a project: `cargo new`, `cargo init`

Cargo is also the package manager for Rust. This means that you can
use Cargo to install and manage bits of other people's code.

- A program or library is called a "crate".
- A package contains one or more crates.
- You can find Crates on http://crates.io
- You list the Crates you want to use in the `Cargo.toml` file
- Your app keeps track of what crates you are using in the `Cargo.lock` file

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## Setting up a Project

Creating a new project is easy!

1. Type `cargo new --bin name-of-my-project`
  * Use `--lib` if you are writing a library
2. `cd` into the new `name-of-my-project` directory

This will create several files and folders for you automatically:

- `Cargo.toml`: metadata about your project and its dependencies
- `.gitignore`: ignores compiled files built by Rust
- `src/lib.rs` or `src/main.rs`: where your Rust code goes

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## `lib.rs` vs `main.rs`

There are 2 main types of projects you can make in Rust: a library and not
a library.

If you are writing a <strong>library</strong>, it means you intend for your
code to be used in someone else's application as a crate or module.
If you want to do this, you should use a `lib.rs`.

If you are writing a <strong>not library</strong>, it means that you'd like
to write code that compiles into a binary that someone can run. If you
want to do this, you need to use a `main.rs`. Inside the `main.rs` you
should have a `main` function that looks like this:

```rust
fn main() {
  // your app code goes here
}
```

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## `rustfmt`

The `rustfmt` tool integrates with Cargo and can format your code for you! To
install it:

```bash
$ rustup component add rustfmt-preview
```

And to use it:

```bash
$ cargo fmt
```

Cargo will re-write your files with the newly formatted code.

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## Hello, world!

If you generate a new program:

```bash
$ cargo new hello-world
$ cd hello-world
```

Cargo will make `src/main.rs` a "Hello World" program for you!

```rust
fn main() {
    println!("Hello, world!");
}
```

Remember, you can run it with `cargo run`:

```bash
$ cargo run
    Compiling hello-world v0.1.0 (file:///C:/hello-world)
Finished dev [unoptimized + debuginfo] target(s) in 2.6 secs
 Running `target\debug\hello-world.exe`
Hello, world!
```

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## Basic Syntax

If we look at "hello world":

```rust
fn main() {
    println!("Hello, world!");
}
```

* `fn` declares a function. In this case, our function is named `main`. `main` will
  be called when your program starts.
* The empty parenthesis means that `main` takes no parameters.
* Function bodies go in curly braces: `{}`
* The `println!` macro (the `!` means it's a macro) prints stuff to the screen!
* Strings go inside double quotes `""`
* Lines end with a semicolon `;`

Try adding another call to `println!` with a second message!

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## `cargo check`

If you want the compiler to check your work, but you don't plan on actually running
your program, you can use `cargo check`. It's faster than `cargo build`:

```bash
$ cargo build
   Compiling hello-world v0.1.0 (file:///C:/hello-world)
    Finished dev [unoptimized + debuginfo] target(s) in 1.21 secs
$ cargo check
   Compiling hello-world v0.1.0 (file:///C:/hello-world)
    Finished dev [unoptimized + debuginfo] target(s) in 0.85 secs
```

For "hello world" that's not much, but on real projects it really adds up!

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## Learning More

There are other "Rust in ten slides" presentations too, but you
may also find these resources useful!

- The Rust Docs, https://doc.rust-lang.org/
- The Rust Book, https://doc.rust-lang.org/book/
- into_rust Screencasts, http://intorust.com/
- The Rust Play Ground, https://play.rust-lang.org/
- Rust by Example, http://rustbyexample.com/
- Rust on exercism.io, http://exercism.io/languages/rust
- New Rustacean Podcast, http://www.newrustacean.com/