Book Image

Clojure High Performance Programming

By : Shantanu Kumar
Book Image

Clojure High Performance Programming

By: Shantanu Kumar

Overview of this book

<p>Clojure is a young, dynamic, functional programming language that runs on the Java Virtual Machine. It is built with performance, pragmatism, and simplicity in mind. Like most general purpose languages, Clojure’s features have different performance characteristics that one should know in order to write high performance code.<br /><br />Clojure High Performance Programming is a practical, to-the-point guide that shows you how to evaluate the performance implications of different Clojure abstractions, learn about their underpinnings, and apply the right approach for optimum performance in real-world programs.<br /><br />This book discusses the Clojure language in the light of performance factors that you can exploit in your own code.</p> <p>You will also learn about hardware and JVM internals that also impact Clojure’s performance. Key features include performance vocabulary, performance analysis, optimization techniques, and how to apply these to your programs. You will also find detailed information on Clojure's concurrency, state-management, and parallelization primitives.</p> <p>This book is your key to writing high performance Clojure code using the right abstraction, in the right place, using the right technique.</p>
Table of Contents (15 chapters)
Clojure High Performance Programming
Credits
About the Author
Acknowledgments
About the Reviewers
www.PacktPub.com
Preface
Index

Performance miscellanea


Besides the major abstractions we saw earlier in the chapter, there are other smaller, but nevertheless very performance-critical, parts of Clojure that we will see in this section.

Disabling assertions in production

Assertions are very useful to catch logical errors in the code during development, but they impose a runtime overhead that you may like to avoid in production environment. Since clojure.core/*assert* is a compile time var, the assertions can be silenced either by binding *assert* to false or by using alter-var-root before the code is loaded. Unfortunately, both the techniques are cumbersome to use. Paul Stadig's library called assertions (https://github.com/pjstadig/assertions) helps with this exact use case by enabling or disabling assertions via command-line argument -ea to the Java Runtime. You must include it in your Leiningen project.clj file as a dependency to use it:

:dependencies [;; other dependencies…
              [pjstadig/assertions "0.1.0"...