Foreword
Foreword, Third Edition
Forward-looking programming languages don’t always make it. Yet Scala is not only surviving but thriving. Some languages never get commercial adoption at all. Those first few companies brave enough to bet their business on your language are hard to find. Other languages get their time in the commercial sun but don’t manage to hang on, like Common Lisp and Smalltalk. They live on as influences, their genes still discernable in contemporary languages. That’s success of a kind, but not what the creators wanted.
Scala has been defying these trends for well over a decade now. Circa 2008, companies such as Twitter and Foursquare brought Scala out of academia and into the commercial world. Since then, the Scala job market and ecosystem have been sustained not only by independent enthusiasts but by superstar open source projects, such as Spark and Kafka, and companies like those on the Scala Center’s advisory board, who collectively employ impressive numbers of Scala programmers.
Can Scala continue to pull it off? Its creator, Martin Odersky, thinks it can and I agree. Scala 3, launching in 2021, is a bold leap into the future of programming. Other languages will be playing catch-up for years to come.
And not for the first time, either. In the years since Scala’s initial success, Java emerged from its long torpor with a parade of Scala-inspired language features. Swift and Rust also show Scala’s influence. Direct competitors have appeared too. Kotlin remains a contender, while others, such as Ceylon, have already fallen by the wayside.
How much innovation is too much? How much is too little? Explorers must be bold but not foolhardy. Dangers lurk in new seas and on new lands, but you’ll never discover anything if you just stay home.
Scala’s bet is that being a better Java isn’t enough to meet programmers’ needs—not even if that better Java is Java itself. For one thing, competing with Java isn’t enough anymore. If Scala’s growth has leveled off somewhat in recent years, perhaps it’s because Java’s has too, and because we’ve already converted all the Java programmers we can hope to convert. We need to show that Scala is also a more-than-worthy alternative to now-mainstream languages, like Python and TypeScript, and insurgent languages, like Rust and Haskell.
The big reason Scala still matters and is worth fighting for is that it fully embraces functional programming. Yes, it’s wonderful that Java has added lambdas and pattern matching, features that come from the functional tradition. But functional programming isn’t just a bag of disconnected individual features. It’s a paradigm shift, a fresh way of thinking. Learning Scala, or any functional language, makes you wonder how you ever programmed any other way.
Learning Scala doesn’t mean forgetting everything you already know. Scala fuses the object-oriented and functional programming traditions into a single language you’ll never grow out of. And though Scala offers its own vibrant ecosystem of libraries, Scala programmers are also free to leverage vast worlds of Java and JavaScript.
The design of Scala 3 retains the same pragmatism that has been crucial to its success all along. My teammates and I at Lightbend, along with our colleagues at the Scala Center and in Martin’s lab, work hard to make migration to new versions smooth, even as we bring you a Christmas-morning’s worth of new toys to play with.
It’s truly remarkable how much of the Scala ecosystem has already made the leap. Scala 3 only just came out this month, but a rich array of libraries and tooling is already available for it.
Whether you’re entirely new to Scala or making the 2 to 3 transition, Dean Wampler is the ideal traveling companion. Some Scala books make you feel like you’re back in a classroom. This one makes you feel like you’re pair-programming with a helpful expert. The text is bristling with practical know-how, with all of the nuances and need-to-knows for when you’re actually at the keyboard, trying to make something run. Dean inspires with how programming in Scala ought to be and is candid about what it is actually like. He gives you tomorrow, and today.
Whatever the future holds for Scala, it will always be known as the language that took functional programming from a daring experiment to a practical, everyday reality.
My fondest wish for this book is that it will find its way into the hands of a new generation of Scala programmers. This new crew will be younger and more diverse than the old guard, and less encumbered by programming’s past. Professors: teach your students Scala! I can’t wait to see what they’ll build.
Foreword, First and Second Edition
If there has been a common theme throughout my career as a programmer, it has been the quest for better abstractions and better tools to support the craft of writing software. Over the years, I have come to value one trait more than any other: composability. If one can write code with good composability, it usually means that other traits we software developers value—such as orthogonality, loose coupling, and high cohesion—are already present. It is all connected.
When I discovered Scala some years ago, the thing that made the biggest impression on me was its composability.
Through some very elegant design choices and simple yet powerful abstractions that were taken from the object-oriented and functional programming worlds, Martin Odersky has managed to create a language with high cohesion and orthogonal, deep abstractions that invites composability in all dimensions of software design. Scala is truly a SCAlable LAnguage that scales with usage, from scripting all the way up to large-scale enterprise applications and middleware.
Scala was born out of academia, but it has grown into a pragmatic and practical language that is very much ready for real-world production use.
What excites me most about this book is that it’s so practical. Dean has done a fantastic job, not only by explaining the language through interesting discussions and samples, but also by putting it in the context of the real world. It’s written for the programmer who wants to get things done.
I had the pleasure of getting to know Dean some years ago when we were both part of the aspect-oriented programming community. Dean holds a rare mix of deep analytical academic thinking and a pragmatic, get-things-done kind of mentality.
You are about to learn how to write reusable components using mixin and function composition; how to write distributed applications using Akka; how to make effective use of advanced features in Scala, such as macros and higher-kinded types; how to utilize Scala’s rich, flexible, and expressive syntax to build domain-specific languages; how to effectively test your Scala code; how to let Scala simplify your big-data problems; and much, much more.
Enjoy the ride. I sure did.
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