Book Image

Mastering Clojure

By : Akhil Wali
Book Image

Mastering Clojure

By: Akhil Wali

Overview of this book

Clojure is a general-purpose language from the Lisp family with an emphasis on functional programming. It has some interesting concepts and features such as immutability, gradual typing, thread-safe concurrency primitives, and macro-based metaprogramming, which makes it a great choice to create modern, performant, and scalable applications. Mastering Clojure gives you an insight into the nitty-gritty details and more advanced features of the Clojure programming language to create more scalable, maintainable, and elegant applications. You’ll start off by learning the details of sequences, concurrency primitives, and macros. Packed with a lot of examples, you’ll get a walkthrough on orchestrating concurrency and parallelism, which will help you understand Clojure reducers, and we’ll walk through composing transducers so you know about functional composition and process transformation inside out. We also explain how reducers and transducers can be used to handle data in a more performant manner. Later on, we describe how Clojure also supports other programming paradigms such as pure functional programming and logic programming. Furthermore, you’ll level up your skills by taking advantage of Clojure's powerful macro system. Parallel, asynchronous, and reactive programming techniques are also described in detail. Lastly, we’ll show you how to test and troubleshoot your code to speed up your development cycles and allow you to deploy the code faster.
Table of Contents (19 chapters)
Mastering Clojure
Credits
About the Author
About the Reviewer
www.PacktPub.com
Preface
References
Index

Using Reactive Extensions


Reactive Extensions (written as Rx) are a generalized implementation of reactive programming that can be used to model event and data streams. Rx can be thought of as an object-oriented approach to reactive programming, in the sense that an event stream is an object with certain methods and properties. In Rx, asynchronous event streams are termed as observables. An entity or object that subscribes to events from an observable is called an observer. Reactive extensions are essentially a library of functions, or methods, to manipulate observables and create objects that conform to the observer-observable pattern. For example, an observable can be transformed using the Rx variants of the map and filter functions, as shown in the following illustration:

As shown previously, an observable can be described as a collection of values that vary over a period of time. It's quite evident that observables can be treated as a sequence of values using the Rx-flavored variants...