Book Image

Elixir Cookbook

By : Paulo Pereira
Book Image

Elixir Cookbook

By: Paulo Pereira

Overview of this book

Table of Contents (16 chapters)
Elixir Cookbook
Credits
About the Author
About the Reviewers
www.PacktPub.com
Preface
Index

Preface

More than ever, programmers need tools and languages that enable them to develop applications that take full advantage of all the resources available in a system. A few years ago, programs began to speed up just because CPUs were getting progressively faster. However, the "speed limit" has now been hit, and processors are no longer getting faster.

Instead, we are getting more cores available per chip. Today, the challenge is how to take advantage of all that extra power. Elixir helps us do this!

Elixir is a dynamic, functional programming language created by José Valim. It is compatible with the Erlang virtual machine and ecosystem. It focuses on scalability and fault tolerance. With its concurrency model and its ability to handle distribution seamlessly, it makes the task of implementing resilient and efficient systems easier, even fun!

In this cookbook, you will find recipes covering some of the language tooling and concepts. You will find out that no special powers are needed to write concurrent programs or code that can be executed by other machines. You will find out that all you need is an expressive and powerful language, such as Elixir.

What this book covers

Chapter 1, Command Line, introduces Interactive Elixir (IEx), which is a command line tool that allows us to execute and evaluate code. This chapter also introduces Mix, which is an Elixir tool to create and manage projects.

Chapter 2, Data Types and Structures, focuses on some concepts of the language: immutability, pattern matching, and lazy evaluation.

Chapter 3, Strings and Binaries, shows us how to manipulate strings in Elixir.

Chapter 4, Modules and Functions, focuses on the building blocks of Elixir applications, from module directives to pattern matching in function definitions.

Chapter 5, Processes and Nodes, shows you that spawning multiple processes to perform asynchronous computations or connecting multiple machines and executing code on any of them is not as hard as it seems. Elixir makes the task easier, and we explore specific examples.

Chapter 6, OTP – Open Telecom Platform, talks about OTP, which is a systematization of common programming concepts. It allows us to develop large-scale systems on a solid foundation. In this chapter, we will explore some of its constructs.

Chapter 7, Cowboy and Phoenix, is all about the Web! It discusses a range of topics, from serving static files to implementing websockets, or using a fully-featured web framework.

Chapter 8, Interactions, interacts with our host operating system and talks about external systems such as Postgresql or Redis. We will also build a Twitter feed parser.

Appendix, Installation and Further Reading, covers references for installing Elixir, Redis, and PostgreSQL, as well as for further reading.

What you need for this book

You will need to have Elixir installed as well as Erlang, its only dependency. In this book, we will also be using Postgresql and Redis.

Who this book is for

This book is intended for users with some knowledge of the Elixir language syntax and basic data types/structures. Although this is a cookbook and no sequential reading is required, the book's structure will allow less advanced users who follow it to be gradually exposed to some of Elixir's features and concepts specific to functional programming. To get the most out of this book, you need to have some familiarity with Erlang/Elixir philosophy and concepts.

Sections

In this book, you will find several headings that appear frequently (Getting ready, How to do it, How it works, There's more, and See also).

To give clear instructions on how to complete a recipe, we use these sections as follows:

Getting ready

This section tells you what to expect in the recipe, and describes how to set up any software or any preliminary settings required for the recipe.

How to do it…

This section contains the steps required to follow the recipe.

How it works…

This section usually consists of a detailed explanation of what happened in the previous section.

There's more…

This section consists of additional information about the recipe in order to make the reader more knowledgeable about the recipe.

See also

This section provides helpful links to other useful information for the recipe.

Conventions

In this book, you will find a number of text styles that distinguish between different kinds of information. Here are some examples of these styles and an explanation of their meaning.

Code words in text, database table names, folder names, filenames, file extensions, pathnames, dummy URLs, user input, and Twitter handles are shown as follows: "The Elixir standard library has a List module defined."

A block of code is set as follows:

code\greeter.ex
defmodule Greeter do
def greet(name \\ "you") do
"Hello #{name} !"
end
end

When we wish to draw your attention to a particular part of a code block, the relevant lines or items are set in bold:

supervised_app/mix.exs
def application do
  [applications: [:logger],
  mod: {SupervisedApp, []}]
end

Any command-line input or output is written as follows:

> mix help

New terms and important words are shown in bold. Words that you see on the screen, for example, in menus or dialog boxes, appear in the text like this: "Select the Load Charts tab to see graphical representation of memory usage, IO, and scheduler utilization over time."

Note

Warnings or important notes appear in a box like this.

Tip

Tips and tricks appear like this.

Reader feedback

Feedback from our readers is always welcome. Let us know what you think about this book—what you liked or disliked. Reader feedback is important for us as it helps us develop titles that you will really get the most out of.

To send us general feedback, simply e-mail , and mention the book's title in the subject of your message.

If there is a topic that you have expertise in and you are interested in either writing or contributing to a book, see our author guide at www.packtpub.com/authors.

Customer support

Now that you are the proud owner of a Packt book, we have a number of things to help you to get the most from your purchase.

Downloading the example code

You can download the example code files from your account at http://www.packtpub.com for all the Packt Publishing books you have purchased. If you purchased this book elsewhere, you can visit http://www.packtpub.com/support and register to have the files e-mailed directly to you.

Errata

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To view the previously submitted errata, go to https://www.packtpub.com/books/content/support and enter the name of the book in the search field. The required information will appear under the Errata section.

Piracy

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Questions

If you have a problem with any aspect of this book, you can contact us at , and we will do our best to address the problem.