The other recipes in the chapter describe functions already built into Sass. In this recipe, you will learn how to extend Sass with your own custom functions.
This recipe requires some basic knowledge of Ruby programming. To learn more about Ruby, you can read the Ruby and MongoDB Web Development Beginner's Guide book by Gautam Rege. You can find more about Rege's book at https://www.packtpub.com/web-development/ruby-and-mongodb-web-development-beginners-guide. Also, read the Installing Sass for command line usage recipe of Chapter 1, Getting Started with Sass, to find out how to compile your SCSS code into CSS code. This recipe uses the same SCSS code as the one used for the Introspection Functions recipe of this chapter.