Put the fun back in functional programming.

Crush the concepts. Cut the confusion. Writing declarative code has never been easier.
Designed for CSX has information for every challenge in the CSX Callbacks and Higher Order Functions module. This guide isn't affiliated with CSX, but it was built by people who have previously completed it. If we can do it, you can do it.
Seeing is Believing
Looking for more than just a working solution? Every challenge on has a step-by-step visual walkthrough of the algorithm behind it. You won't just learn which solutions work, you'll learn why they work by seeing them in action.
Crack the Code
Each walkthrough on this site is followed by a video of a real-time coding demonstration, showing a possible implementation of the solution. With the entire guide available for free in both video and text format, it's time to learn things your way.
Find the clarity in declarative code.

It's time to break through your blocks. Your higher-order function journey begins today!