Book Image

Rust Standard Library Cookbook

By : Jan Hohenheim, Daniel Durante
Book Image

Rust Standard Library Cookbook

By: Jan Hohenheim, Daniel Durante

Overview of this book

Mozilla’s Rust is gaining much attention with amazing features and a powerful library. This book will take you through varied recipes to teach you how to leverage the Standard library to implement efficient solutions. The book begins with a brief look at the basic modules of the Standard library and collections. From here, the recipes will cover packages that support file/directory handling and interaction through parsing. You will learn about packages related to advanced data structures, error handling, and networking. You will also learn to work with futures and experimental nightly features. The book also covers the most relevant external crates in Rust. By the end of the book, you will be proficient at using the Rust Standard library.
Table of Contents (12 chapters)

How it works...

By the usage of compose! in main [30 and 34], you should see clearly what it does: it takes as many closures as you want, and combines them into a new closure that runs them one by one. This is really useful for runtime user-driven functionality composition.

The macro is implemented similarly to the standard macro for variable arguments from Chapter 1, Learning the Basics; Accepting a variable number of arguments, with its edge case being a single closure [6]. When encountering more, it will recursively go through them and combine them in pairs by calling the helper function compose_two [14]. Usually, type parameters are written as a single character, but we are using full words for them in this recipe for readability reasons, as there are quite a number of types involved. The type constraints used should illustrate how the types are used pretty well [18 to 20]:

FunOne: Fn(Input) -> Intermediate,
FunTwo: Fn(Intermediate) -> Output,

FunOne is a closure...