Getting started with Scala

If you have already installed Scala, you can skip this paragraph. One can get the latest Scala download from http://www.scala-lang.org/download/. I used Scala version 2.11.7 on Mac OS X El Capitan 10.11.5. You can use any other version you like, but you might face some compatibility problems with other packages such as Spark, a common problem in open source software as the technology adoption usually lags by a few released versions.

If you installed Scala correctly, after typing scala, you should see something similar to the following:

[akozlov@Alexanders-MacBook-Pro ~]$ scala
Welcome to Scala version 2.11.7 (Java HotSpot(TM) 64-Bit Server VM, Java 1.8.0_40).
Type in expressions to have them evaluated.
Type :help for more information.

scala>

This is a Scala read-evaluate-print-loop (REPL) prompt. Although Scala programs can be compiled, the content of this chapter will be in REPL, as we are focusing on interactivity with, maybe, a few exceptions. The :help command provides a some utility commands available in REPL (note the colon at the start):