Write code that writes code with Elixir macros. Macros make metaprogramming possible and define the language itself. In this book, you'll learn how to use macros to extend the language with fast, maintainable code and share functionality in ways you never thought possible. You'll discover how to extend Elixir with your own first-class features, optimize performance, and create domain-specific languages. Metaprogramming is one of Elixir's greatest features. Maybe you've played with the basics or written a few macros. Now you want to take it to the next level. This book is a guided series of metaprogramming tutorials that take you step by step to metaprogramming mastery. You'll extend Elixir with powerful features and write faster, more maintainable programs in ways unmatched by other languages. You'll start with the basics of Elixir's metaprogramming system and find out how macros interact with Elixir's abstract format. Then you'll extend Elixir with your own first-class features, write a testing framework, and discover how Elixir treats source code as building blocks, rather than rote lines of instructions. You'll continue your journey by using advanced code generation to create essential libraries in strikingly few lines of code. Finally, you'll create domain-specific languages and learn when and where to apply your skills effectively. When you're done, you will have mastered metaprogramming, gained insights into Elixir's internals, and have the confidence to leverage macros to their full potential in your own projects.

Don't accept the compromise between fast and beautiful: you can have it all. Phoenix creator Chris McCord, Elixir creator Jose Valim, and award-winning author Bruce Tate walk you through building an application that's fast and reliable. At every step, you'll learn from the Phoenix creators not just what to do, but why. Packed with insider insights and completely updated for Phoenix 1.4, this definitive guide will be your constant companion in your journey from Phoenix novice to expert, as you build the next generation of web applications. Phoenix is the long-awaited web framework based on Elixir, the highly concurrent language that combines a beautiful syntax with rich metaprogramming. The best way to learn Phoenix is to code, and you'll get to attack some interesting problems. Start working with controllers, views, and templates within the first few pages. Build an in-memory context, and then back it with an Ecto database layer, complete with changesets and constraints that keep readers informed and your database integrity intact. Craft your own interactive application based on the channels API for the real-time applications that this ecosystem made famous. Write your own authentication plugs, and use the OTP layer for supervised services. Organize code with modular umbrella projects. This edition is fully updated for Phoenix 1.4, with a new chapter on using Channel Presence to find out who's connected, even on a distributed application. Use the new generators and the new ExUnit features to organize tests and make Ecto tests concurrent. This is a book by developers and for developers, and we know how to help you ramp up quickly. Any book can tell you what to do. When you've finished this one, you'll also know why to do it. What You Need: To work through this book, you will need a computer capable of running Erlang 18 or higher, Elixir 1.5 or higher, and Phoenix 1.4 or higher. A rudimentary knowledge of Elixir is also highly recommended.