Gain insights into metaprogramming in Elixir. Delve into macros and discover how to elevate your coding skills, creating powerful libraries with concise, efficient code.

_Metaprogramming Elixir by The Pragmatic Programmer_468 x 60 copy.png

elixir.tar.gz

elixir

elixir-testing

elixir-copy

Get introduced to the concept of metaprogramming. Learn how to level up your programming skills by discovering the full potential of the macro system in Elixir. Understand the ins and outs of metaprogramming at a fundamental level and write incredible libraries by doing more with less code.

Metaprogramming in Elixir

Before we can implement the `test` macro, we need to address a missing piece of our implementation. A user can define multiple test cases, but we have can't track each test-case definition for inclusion within `MathTest.run/0`. Fortunately, Elixir solves this use case via module attributes.

# Utilizing module attributes
__Module attributes__ allow us to store data in the module at compile time. They are often used in places where constants would be applied in other languages, but Elixir provides other tricks for us to exploit during compilation. We can keep an appended list of registration during the compile phase by taking advantage of the `accumulate: true` option when registering an attribute. After the module is compiled, the attribute contains a list of all registrations that occurred during compilation. Let’s see how this can be used for our `test` macro.

Our `test` macro will accept two arguments: 
- A string description 
- A keyword list for the `do/end` code block.

Let's modify our previous `assertion` module in the following way:


Learn about module attributes and how they help in keeping track of test cases.

Introduction

The Language of Macros

Extending Elixir with Metaprogramming

Advanced Compile-Time Code Generation

Code Generation from Git API

How to Test Macros

Create an HTML Domain-Specific Language

With Great Power Comes Great Responsibility (and Fun!)

Using Module Attributes for Code Generation

Utilizing module attributes