Functional Programming Strategies (Draft)

Most programming books teach syntax; Functional Programming Strategies teaches you how to think. The right mental models lead naturally to better code, and functional programming's theoretical foundations provide exceptionally useful mental models—ones that scale from simple functions to complex systems. Over 25 years of professional programming I've refined a mental toolkit that I call functional programming strategies. These strategies form the core of the book. For example, “types as constraints” is the strategy of representing semantic constraints in the type system, while “following the types” is the strategy of using type information to guide the implementation. Every strategy is illustrated with practical case studies showing how they apply to real code.

To get the most from Functional Programming Strategies you should be proficient with a programming language and ready to dive into where theory and practice meet. This is not an introductory programming book, but one on the deep concepts and connections behind programming. The book's examples use Scala—its expressivity makes it easy to demonstrate the strategies, while its industry adoption means you can apply these techniques immediately in production code. The strategies, however, are language agnostic and translate to other modern typed languages, such as Rust, Kotlin, OCaml, or Typescript.

The book is currently a draft, though at over 400 pages it already has a lot of content. If you purchase the draft you'll get access to updates and the final version when it is ready. You may also want to sign up to the mailing list to be notified when the book is released.