Book Image

Hands-On Reactive Programming with Clojure - Second Edition

By : Konrad Szydlo, Leonardo Borges
Book Image

Hands-On Reactive Programming with Clojure - Second Edition

By: Konrad Szydlo, Leonardo Borges

Overview of this book

Reactive Programming is central to many concurrent systems, and can help make the process of developing highly concurrent, event-driven, and asynchronous applications simpler and less error-prone. This book will allow you to explore Reactive Programming in Clojure 1.9 and help you get to grips with some of its new features such as transducers, reader conditionals, additional string functions, direct linking, and socket servers. Hands-On Reactive Programming with Clojure starts by introducing you to Functional Reactive Programming (FRP) and its formulations, as well as showing you how it inspired Compositional Event Systems (CES). It then guides you in understanding Reactive Programming as well as learning how to develop your ability to work with time-varying values thanks to examples of reactive applications implemented in different frameworks. You'll also gain insight into some interesting Reactive design patterns such as the simple component, circuit breaker, request-response, and multiple-master replication. Finally, the book introduces microservices-based architecture in Clojure and closes with examples of unit testing frameworks. By the end of the book, you will have gained all the knowledge you need to create applications using different Reactive Programming approaches.
Table of Contents (15 chapters)

Transducers

Before we finish up with our core.async portion of this book, we should mention what came up in Clojure 1.7, as well as how this affects core.async.

One of the big changes in this release was the introduction of transducers. We will not cover the nuts and bolts of it here, but rather focus on what it means at a high-level with examples using both Clojure sequences and core.async channels.

If you would like to know more, I recommend Carin Meier's Green Eggs and Transducers blog post[4]. It's a great place to start.

Additionally, the official Clojure documentation site on the subject is another useful resource[5].

Let's get started by creating a new Leiningen project:

$ lein new core-async-transducers  

Now, open your project.clj file and make sure you have the right dependencies:

... 
  :dependencies [[org.clojure/clojure "1.9.0"] 
    ...