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 4. Metaprogramming with Macros

Programmers often stumble into situations where they would like to add features or constructs to their programming language of choice. Generally, if a feature would have to be added to a language, the language's compiler or interpreter would need some modification. Alternatively, Clojure (and other Lisps as well) uses macros to solve this problem. The term metaprogramming is used to describe the ability to generate or manipulate a program's source code by using another program. Macros are a metaprogramming tool that allow programmers to easily add new features to their programming language.

Lisps are not the only languages with support for macro-based metaprogramming. For example, in C and C++, macros are handled by the compiler's preprocessor. In these languages, before a program is compiled, all macro calls in the program's source code are replaced by their definitions. In this sense, macros are used to generate code through a form of text substitution...