Scala, the good parts

Scala is a large language that is popular because of its approachability for new developers. This banquet of features is a problem because many aspects of Scala, like implicit conversions and dynamics, can get you into trouble. To successfully use Scala, you need to research the language and have a very strong opinion on which parts are right for you, creating your own definition of Scala, the good parts. You can disable the parts you do not want using a system called feature flags.

In the previous radar we had two JVMbased functional programming languages, Clojure and Scala, in our Assess category. We had expressed a slight preference for Clojure because it is the smaller and more focused language. Since the last radar we have realized that the wider applicability of Scala makes it more approachable for enterprise developers, and we have witnessed great successes in the adoption of Scala. Consequently we have moved Scala into our Trial category. Pay careful attention to the idiomatic use of Scala if it is introduced to a new team to avoid "Java without semicolons" or Perl styles.

The functional languages F#, Clojure and Scala still reside in the assess ring of the radar. Interest in functional languages continues to grow. Two characteristics of functional languages in particular are driving this interest, immutability with its implications for parallelism and functions as first class objects. While the introduction of closures to C# brings some of the latter capability, functional languages are almost synonymous with immutability. The placement of these languages within the assess ring indicates our view of their relative maturity and appropriateness. F#, based on OCaml, is fully supported within the Visual Studio toolset. F# includes support for objects and imperative constructs in addition to functional language constructs in a natural way. Scala, like F#, combines the object and functional paradigms, although the syntax of Scala is more Java-like. Clojure began as a JVM language and is now available on the .NET CLR. Clojure does allow for mutable state although it has an extensive set of immutable persistent data structures, all supporting multi-threaded applications. There are many similarities between these three languages, but at the moment we believe F# and Clojure to be better suited to most organizations for assessing than Scala. More work clearly needs to be done to validate this assertion.

In the previous radar, we lumped functional languages together in a group. For this version, we’ve exploded that group and started calling out the ones interesting to us. Of the current crop of functional languages, the one we like the most is Clojure: a simple, elegant implementation of Lisp on the JVM. The other two that we fi nd interesting are Scala (a re-thinking of Java in functional form) and F#, the OCaml derivative from Microsoft that now appears “in the box” in Visual Studio 2010.