Book Image

Mastering Rust. - Second Edition

By : Rahul Sharma
Book Image

Mastering Rust. - Second Edition

By: Rahul Sharma

Overview of this book

Rust is an empowering language that provides a rare combination of safety, speed, and zero-cost abstractions. Mastering Rust – Second Edition is filled with clear and simple explanations of the language features along with real-world examples, showing you how you can build robust, scalable, and reliable programs. This second edition of the book improves upon the previous one and touches on all aspects that make Rust a great language. We have included the features from latest Rust 2018 edition such as the new module system, the smarter compiler, helpful error messages, and the stable procedural macros. You’ll learn how Rust can be used for systems programming, network programming, and even on the web. You’ll also learn techniques such as writing memory-safe code, building idiomatic Rust libraries, writing efficient asynchronous networking code, and advanced macros. The book contains a mix of theory and hands-on tasks so you acquire the skills as well as the knowledge, and it also provides exercises to hammer the concepts in. After reading this book, you will be able to implement Rust for your enterprise projects, write better tests and documentation, design for performance, and write idiomatic Rust code.
Table of Contents (19 chapters)

A more involved macro – writing a DSL for HashMap initialization

Armed with the knowledge of repetitions and token tree types, let's build something practical using repetitions in macro_rules!. In this section, we'll build a crate that exposes a macro that allows you to create HashMaps such as the following:

let my_map = map! {
1 => 2,
2 => 3
};

This is more concise and readable compared to manually calling HashMap::new(), followed by one or more insert calls. Let's create a new cargo project by running cargo new macro_map --lib with the initial block for macro_rules!:

// macro_map/lib.rs

#[macro_export]
macro_rules! map {
// todo
}

Since we want the users to use our macros, we need to add a #[macro_export] attribute on this macro definition. Macros are private by default in a module, which is similar to other items. We'll call our macro...