If you pry into the beating heart of any Rails application, any testing framework, any beautiful DSL, you’ll find it filled with metaprogramming: code that writes code. In fact, a lot of the features Ruby devs use would be impossible without it. Yet many of us prefer to avoid metaprogramming in our own code. This is a brief tour of metaprogramming for Rubyists. http://www.rubyletter.com/newsletter/2017/05/26/metaprogramming.html