Book Image

Mastering Functional Programming

Book Image

Mastering Functional Programming

Overview of this book

Functional programming is a paradigm specifically designed to deal with the complexity of software development in large projects. It helps developers to keep track of the interdependencies in the code base and changes in its state in runtime. Mastering Functional Programming provides detailed coverage of how to apply the right abstractions to reduce code complexity, so that it is easy to read and understand. Complete with explanations of essential concepts, practical examples, and self-assessment questions, the book begins by covering the basics such as what lambdas are and how to write declarative code with the help of functions. It then moves on to concepts such as pure functions and type classes, the problems they aim to solve, and how to use them in real-world scenarios. You’ll also explore some of the more advanced patterns in the world of functional programming such as monad transformers and Tagless Final. In the concluding chapters, you’ll be introduced to the actor model, which you can implement in modern functional languages, and delve into parallel programming. By the end of the book, you will be able to apply the concepts of functional programming and object-oriented programming (OOP)in order to build robust applications.
Table of Contents (17 chapters)

But how do we get rid of the side effects?

If you come from a purely imperative background, you may be quite confused at this point. Purely functional programming says that you need to eliminate all the side effects. But can you imagine a program without logging? And what would be the use of a web API that cannot connect to a network? If we cannot throw an exception, how do we specify the erroneous behavior of the program?

The side effects specified previously are essential to most modern applications, and it is usually not possible to imagine a reasonable program without side effects.

Therefore, it would be wrong to say that purely functional programming eliminates side effects from your program completely. Instead, it would be more precise to say that it eliminates side effects from your business logic. It pushes side effects away from the parts of your application that matter...