Summary

You should now have a better understanding of functional programming and its benefits, as well as how Kotlin approaches this topic. We've discussed the concepts of immutability and pure functions, and how combining these results in more testable code that is easier to maintain.

We discussed how Kotlin supports closures, which allow a function to access the variables of the function that wraps it and effectively store the state between executions. This enables techniques such as currying and memoization that allow us to fix some of the function arguments (by acting as defaults) and remember the value returned from a function in order to avoid recalculating it.

We learned that Kotlin uses the tailrec keyword to allow the compiler to optimize tail recursion. We also looked at higher-order functions, expressions versus statements, and pattern matching. All of these concepts allow us to write code that is easier to test and has less risk of concurrency bugs.

In...