Basics of Functional Programming

This chapter covers the basic principles of functional programming, focusing on how Kotlin supports this paradigm. This includes concepts such as higher-order functions, lambdas, immutability, and the use of functions as first-class citizens. It will also explore how Kotlin eases the transition from an object-oriented approach to a functional one, emphasizing the advantages that functional programming brings in terms of flexibility and code maintainability.

We will explain what inline functions are in Kotlin and how they allow for improved performance. The key point is that functions marked as inline avoid the overhead of function calls by “inserting” the body of the function directly into the code where it is called. This becomes especially useful when working with lambdas or higher-order functions, since inlining reduces the additional object creation and call overhead normally associated with them. We will also provide examples...