I was not always this way… I was once obsessed with objects. I loved modeling the "real world". I was the inventor of synthetic automatons, tinkering through the night with masterful precision. The creator of sentient puppets, fingers dancing on the keyboard to give them life -- a real 1337 h4x0r Geppetto. Yet, after 5 solid years of writing object-oriented code, I was never quite satisfied with the outcome. It just never worked out well for me. I felt like a lousy programmer. I even lost faith that a simple, flexible codebase of decent scale was possible.
I figured I'd try something different: Functional Programming. I began to dabble with functional ideas in my everyday codebase, and much to my coworkers' dismay, hadn't the slightest clue what I was doing. The code I wrote in those days was awful. Atrocious. Digital sewage. The reason was a lack of clear vision or goal on what I was even trying to accomplish. My Jiminy-Coding-Cricket, if you like, was not there to guide me. It took a long time and a lot of garbage programs to figure out how to FP.
Now, after all that messy exploration, I feel that pure Functional Programming has delivered on its promise. Readable programs do exist! Reuse does exist! I no longer invent, but rather discover my model. I've become a rogue detective uncovering a vast conspiracy, cork board pinned full of mathematical evidence. A digital-age Cousteau logging the characteristics of this bizarre land in the name of science! It's not perfect and I still have a lot to learn, but I've never been more satisfied in my work and pleased with the outcome.
Had this book existed when I was starting out, my transition into the world of Functional Programming would have been much easier and less destructive. This book is two-fold (right and left): it will not only teach you how to use various constructs from FP effectively in your daily code, but more importantly, provide you with an aim; guiding principles that will keep you on track.
This book is a terrific place to begin your FP journey. Take it away, Kyle...
-Brian Lonsdorf (@drboolean)