Functional Programming, Simplified: (Scala Edition) (Paperback)

If you’ve had trouble trying to learn Functional Programming (FP), you’re not alone. In this book, Alvin Alexander — author of the Scala Cookbook and former teacher of Java and Object-Oriented Programming (OOP) classes — writes about his own problems in trying to understand FP, and how he finally conquered it.

What he originally learned is that experienced FP developers are driven by two goals: to use only immutable values, and write only pure functions. What he later learned is that they have these goals as the result of another larger goal: they want all of their code to look and work just like algebra.

While that sounds simple, it turns out that these goals require them to use many advanced Scala features — which they often use all at the same time. As a result, their code can look completely foreign to novice FP developers. As Mr. Alexander writes, “When you first see their code it’s easy to ask, ‘Why would anyone write code like this?’”

Mr. Alexander answers that “Why?” question by explaining the benefits of writing pure functional code. Once you understand those benefits — your motivation for learning FP — he shares five rules for programming in the book:

• All fields must be immutable (‘val’ fields).
• All functions must be pure functions.
• Null values are not allowed.
• Whenever you use an ‘if’ you must also use an ‘else’.
• You won’t create OOP classes that encapsulate data and behavior; instead you’ll design data structures using Scala ‘case’ classes, and write pure functions that operate on those data structures.

About the Author

Alvin took the circuitous route to software development. He managed to get a degree in Aerospace Engineering from Texas A&M University, while all he was really trying to do was play baseball. Once he became a practicing engineer, he realized he liked software and programming more than engineering. So in approximate order he taught himself Fortran, C, Unix, network administration, sed, awk, Lisp, Perl, Java, JavaScript, Python, Ruby, JRuby, PHP, and Scala. During this process he started a software consulting firm, grew it to fifteen people, sold it, and moved to Alaska. After returning to the “Lower 48,” he self-published two books (“How I Sold My Business: A Personal Diary”, and “Zen and the Art of Consulting”), and then wrote the “Scala Cookbook” for O’Reilly. He also created alvinalexander.com, which receives millions of page views every year.