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

Chapter 8. Leveraging Asynchronous Tasks

The term asynchronous programming refers to defining tasks that are executed asynchronously on different threads of execution. While this is similar to multithreading, there are a few subtle differences. Firstly, a thread or a future will remain allocated to a single operating system thread until completion. This leads to the fact that is there can only be a limited number of futures that can be executed concurrently, depending on the number of processing cores available. On the other hand, asynchronous tasks are scheduled for execution on threads from a thread pool. This way, a program can have thousands, or even millions of asynchronous tasks running concurrently. An asynchronous task can be suspended at any time, or parked, and the underlying thread of execution can be reallocated to another task. Asynchronous programming constructs also allow the definition of an asynchronous task to look like a sequence of synchronous calls, but each call could...