So far, we've made good progress over the last eight chapters. You've already learned the concepts of functional programming (FP) and some awesome Kotlin features such as coroutines and delegates, which are not exactly from FP theories (in fact, delegates are from the OOP paradigm), but all of them enable us to get more benefits out of FP.

This short chapter is dedicated to combining other programming principles/paradigms with FP to get the best output from them. Here's a list of the topics that we will cover in this chapter:

• Combining FP with OOP
• Functional reactive programming
• Introduction to RxKotlin

So, let's get started.