A long time ago, when the Earth’s crust had just cooled, I learned Java. Some years later, my best friend told me about Clojure, a functional language that compiles to the JVM. The idea was intriguing to me, but at that point, I felt Clojure was maybe a little niche (my friend had pitched Clojure as a language to do massively parallel simulations). Since then, other languages targeting the JVM had popped up. I re-entered the fray with Scala while playing with Spark, and am aware of at least one group that uses Scala on a regular basis.

Language features

Scala is an object-oriented programming language due to objects being first-class entities, ie. everything is an object. Scala is also a functional programming language, with emphasis on recursion, minimizing side-effects and being able to pass functions as arguments.

Despite their similarities, Scala’s syntax can trip up Java programmers since some common things in Java (static keyword, break statements, etc. ) do not exist in Scala and other things are subtly different (infix statements).

Building Scala code

You can compile and link Scala code with sbt, the predominant build tool. However, it is by no means the only option. Others include Gradle and Mill, the latter which created to address some of sbt’s perceived shortcomings.

The actual building process is streamlined using modern IDEs, most notably IntelliJ, which was designed for JVM-targeting languages, but also VSCode (using its Metals extension).

Regardless of the build system you choose, you will have to do some setup to get your Scala code to compile. You can call sbt/Mill manually, or have them watch source files to automatically recompile when there are changes.

If you instead would like to code and run a small project as quickly as possible, Ammonite turns your Scala files into self-contained executable scripts by compiling transparently behind the scene. Ammonite also adds some features to the Scala REPL.