Functional Programming in Kotlin is a reworked version of the bestselling Functional Programming in Scala, with all code samples, instructions, and exercises translated into the powerful Kotlin language. In this authoritative guide, you’ll take on the challenge of learning functional programming from first principles, and start writing Kotlin code that’s easier to read, easier to reuse, better for concurrency, and less prone to bugs and errors.
I've spent over two months with this book - which is frankly not that much, keeping in mind that it's primarily an exercise book - all about applying functional paradigms in practice (in Kotlin, ofc). Even though I spent so much time on a single book, I didn't go carefully through every exercise (!) - but I feel excused: that was not my goal this time. I've already done my functional baptism of fire in 2014 when I went through the original "red" FP in Scala (my review here: https://www.goodreads.com/review/show...). This time, the idea was to get familiar (nearly habitual) with idiomatic, functional Kotlin. So it was more about Kotlin itself (beyond syntax) than FP.
If you are already familiar with Kotlin (as the book assumes so & doesn't start with "Hello world!") AND want to learn what FP really is - this book is definitely for you. But be warned - this will not happen by reading. The idea here is to write (code).
This is an amazing book about functional programming. Doesn't assume much prior knowledge of functional programming yet it deep dives into functional programming fundamentals strongly. For me, it wasn't a fast read but very rewarding.