Book Image

Hands-On Functional Programming in Rust

By : Andrew Johnson
Book Image

Hands-On Functional Programming in Rust

By: Andrew Johnson

Overview of this book

Functional programming allows developers to divide programs into smaller, reusable components that ease the creation, testing, and maintenance of software as a whole. Combined with the power of Rust, you can develop robust and scalable applications that fulfill modern day software requirements. This book will help you discover all the Rust features that can be used to build software in a functional way. We begin with a brief comparison of the functional and object-oriented approach to different problems and patterns. We then quickly look at the patterns of control flow, data the abstractions of these unique to functional programming. The next part covers how to create functional apps in Rust; mutability and ownership, which are exclusive to Rust, are also discussed. Pure functions are examined next and you'll master closures, their various types, and currying. We also look at implementing concurrency through functional design principles and metaprogramming using macros. Finally, we look at best practices for debugging and optimization. By the end of the book, you will be familiar with the functional approach of programming and will be able to use these techniques on a daily basis.
Table of Contents (12 chapters)

Performance, Debugging, and Metaprogramming

  1. How is release mode different from debug mode?

That depends on your Cargo configuration. By default, there are several compiler flags that have different default values in release versus debug mode. One such flag is the opt-level that gets sent to the llvm code generation—the default debug opt-level is 2, and the default release opt-level is 3. These defaults can be changed in Cargo.toml.

  1. How long will an empty loop take to run?

Test it out. Otherwise, it is hard to say for sure on every platform. loop will always be an infinite loop. while true should maybe also be an infinite loop, but will generate a warning. for _ in 0..99999999 {} will be removed at opt-level 3 but not opt-level 2.

  1. What is linear time in Big O notation?

Linear time is O(n) time.

  1. Name a function that grows faster than exponential growth.