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)

Reader

Dependency injection is a mechanism that defines how parts of your program should access other parts of the same program or external resources.

Let's consider a scenario where dependency injection becomes relevant. For example, consider you are writing an application with a database for a bank. The application will include methods for reading and writing the objects of your business domain into the database. For example, you may have a method to create a new user and a method to create a new account for them. These methods depend on the connection to the database. One way to inject this dependency is to pass the database connection object into the methods as arguments:

def createUser(u: User, c: Connection): Int = ???
def createAccount(a: Account, c: Connection): Int = ???

The preceding types are defined as follows:

class Connection
case class User(id: Option[Int], name...