Book Image

Rust Programming By Example

By : Guillaume Gomez, Antoni Boucher
Book Image

Rust Programming By Example

By: Guillaume Gomez, Antoni Boucher

Overview of this book

Rust is an open source, safe, concurrent, practical language created by Mozilla. It runs blazingly fast, prevents segfaults, and guarantees safety. This book gets you started with essential software development by guiding you through the different aspects of Rust programming. With this approach, you can bridge the gap between learning and implementing immediately. Beginning with an introduction to Rust, you’ll learn the basic aspects such as its syntax, data types, functions, generics, control flows, and more. After this, you’ll jump straight into building your first project, a Tetris game. Next you’ll build a graphical music player and work with fast, reliable networking software using Tokio, the scalable and productive asynchronous IO Rust library. Over the course of this book, you’ll explore various features of Rust Programming including its SDL features, event loop, File I/O, and the famous GTK+ widget toolkit. Through these projects, you’ll see how well Rust performs in terms of concurrency—including parallelism, reliability, improved performance, generics, macros, and thread safety. We’ll also cover some asynchronous and reactive programming aspects of Rust. By the end of the book, you’ll be comfortable building various real-world applications in Rust.
Table of Contents (18 chapters)
Title Page
Copyright and Credits
Packt Upsell
Events and Basic Game Mechanisms


Generics are a way to make a function or a type work for multiple types to avoid code duplication. Let's rewrite our max function to make it generic:

fn max<T: PartialOrd>(a: T, b: T) -> T {
    if a > b {
    } else {

The first thing to note is that there's a new part after the function name: this is where we declare the generic types. We declare a generic T type, : PartialOrd after it means that this T type must implement the PartialOrd trait. This is called a trait bound. We then use this T type for both of our parameters and the return type. Then, we see the same function body as the one from our non-generic function. We needed to add the trait bound because, by default, no operation is allowed on a generic type. The PartialOrd trait allows us to use the comparison operators.

We can then use this function with any type that implements PartialOrd:

println!("{}", max('a', 'z'));

This is using static dispatch as opposed to dynamic dispatch, meaning that the compiler will generate a max function specific to char in the resulting binary. Dynamic dispatch is another approach that resolves the right function to call at runtime, which is less efficient.

The Option type

Generics can also be used in a type. The Option type from the standard library is a generic type, defined as such:

enum Option<T> {

This type is useful to encode the possibility of the absence of a value. None means no value, while Some(value) is used when there's a value.