Neal Ford - Functional Thinking: Paradigm Over Syntax

Each chapter in this book shows examples of functional thinking. , describes the gradual process of shifting your perspective from that of an object-oriented, imperative programmer to that of a functional programmer. To illustrate the shift in thinking required, I solve a common problem in both imperative and functional styles. I then do an extensive case study, showing the way a functional perspective (and some helper syntax) can help shift you toward a functional mindset.

, shows examples of common chores you can now cede to your language or runtime. One of the moving parts described by Michael Feathers is state , which is typically managed explicitly in nonfunctional languages. Closures allow you to defer some state-handling to the runtime; I show examples of how that state handling mechanism works underneath. In this chapter, I show how functional thinking also allows you to cede details like accumulation to recursion, and impacts your granularity of code reuse.

, of several levels of optimization, both handwritten and via memoization. At the risk of giving away the ending, memoization wins. Lazy data structures, which defer calculation until necessary, allow you to think differently about data structures. I show how to implement lazy data structures (even in nonfunctional languages) and how to leverage laziness that already exists.

, shows how languages are evolving to become more functional. I also talk about evolutionary language trends such as operator overloading and new dispatch options beyond just method calls, about bending your language toward your problem (not the other way around), and common functional data structures such as Option.

, shows examples of common approaches to problems. I show how design patterns change (or disappear) in the functional programming world. I also contrast code reuse via inheritance versus composition and discuss their explicit and implicit coupling points.

, shows specific long-anticipated functional features that recently appeared in the Java Developer Kit (JDK). I show how Java 8 fits in with the functional thinking from other languages, including the use of higher-order functions (i.e., lambda blocks). I also discuss some clever ways in which Java 8 maintains graceful backward compatibility, and I highlight the Stream API, which allows concise and descriptive workflows. And, finally, I show how Java 8 has added Option to eliminate potential null confusion. I also cover topics such as functional architecture and databases and how the functional perspective changes those designs.

, describes the impact of functional programming on the polyglot world we now live in; we increasingly encounter and incorporate numerous languages on projects. Many new languages are also polyparadigm , supporting several different programming models. For example, Scala supports object-oriented and functional programming. The last chapter discusses the pros and cons of living in a paradigmatically richer world.