How to setup different Scala versions on the same machine?

Question

I want to follow the book on Scala[1] but it uses Scala 3 and I have Scala 2 installed. I want to use both the versions, something on the lines of python2 and python3 .

I tried installing Scala3 on my local using the official source but I could only grasp the project-level working directory. The sbt prompt does not work like a REPL would and I can only open REPL using Scala 2 (I checked the version everytime).

How do I open the REPL of Scala3 given I cannot uninstall Scala2?

Answer 1

The sbt prompt does not work like a REPL

If you execute sbt console from within project directory it will drop you into REPL version corresponding to the project's scalaVersion . For example, executing sbt console within project created with sbt new lampepfl/dotty.g8 would start Scala 3 REPL.

but I could only grasp the project-level working directory

For system-wide installation first install coursier and then execute cs install scala3-repl . This will install Scala 3 REPL alongside the Scala 2 one. Now Scala 3 REPL can be started with scala3-repl command whilst Scala 2 REPL simply with scala command.