Introduction to Metaprogramming

Ruby has impressive metaprogramming capabilities. A traditional program is mainly code that manipulates a data structure and produces output, but metaprogramming allows us to essentially write code that writes code. Metaprogramming is one of Ruby's most powerful features: it lets you perform tasks in a few minutes that may take hours to do in other languages. By cleverly planning your code and applying the techniques mentioned here, you’ll be able to write code that is DRYer, lighter, more intuitive and more scalable.

In this section we'll be discussing and working through the following metaprogramming concepts:

• Mass assignment
• Keyword arguments

Ruby's metaprogramming features offer a lot of functionality. You could, in theory, write everything from scratch yourself, but doing that is very inefficient. In this section of lessons and labs, we'll reveal how metaprogramming makes sense, and is very needed in many situations.

A word of caution: the code in this section will be among the most abstract that we'll deal with to date, so don't worry if the concepts don't make sense immediately! It takes a lot of practice and a bit of re-training your programming brain to identify the kinds of problems that can be solved with metaprogramming.