Book Image

Learning Elixir

By : Kenny Ballou, Kenneth Ballou
Book Image

Learning Elixir

By: Kenny Ballou, Kenneth Ballou

Overview of this book

Elixir, based on Erlang’s virtual machine and ecosystem, makes it easier to achieve scalability, concurrency, fault tolerance, and high availability goals that are pursued by developers using any programming language or programming paradigm. Elixir is a modern programming language that utilizes the benefits offered by Erlang VM without really incorporating the complex syntaxes of Erlang. Learning to program using Elixir will teach many things that are very beneficial to programming as a craft, even if at the end of the day, the programmer isn't using Elixir. This book will teach you concepts and principles important to any complex, scalable, and resilient application. Mostly, applications are historically difficult to reason about, but using the concepts in this book, they will become easy and enjoyable. It will teach you the functional programing ropes, to enable them to create better and more scalable applications, and you will explore how Elixir can help you achieve new programming heights. You will also glean a firm understanding of basics of OTP and the available generic, provided functionality for creating resilient complex systems. Furthermore, you will learn the basics of metaprogramming: modifying and extending Elixir to suite your needs.
Table of Contents (16 chapters)
Learning Elixir
Credits
About the Author
About the Reviewers
www.PacktPub.com
Preface
Index

Applications


Now that we have most of the basics of processes in Elixir, let's try out some examples and applications.

There will be a progression through these examples. We will start pretty small and grow in complexity.

Ping pong

Let's start with a very basic example where one process sends a :ping message to another process. The receiving process will send a :pong message in response.

We will start with a module that looks very similar to the module we created for storing state in a process, except that we have no need for state, this module will only listen for the :ping messages and return :pong:

defmodule PingPong do

  def start_link do
    spawn_link(fn -> loop() end)
  end

  defp loop do
    receive do
      {:ping, sender} ->
        send sender, {:pong, self}
    end
    loop
  end
end

We start with the start_link/0 function that spawns a new process context and kicks off our internal loop. From the loop, we block with the receive do expression. Once the process receives a :ping...