Scala 3 SBT Project

This contains the basic sbt configuration needed to run Scala 3 code.

Installation

1. Check that you have the "Scala (Metals)" and "Scala Syntax (official)" extensions installed in VSCode.

2. Clone this repo: git clone git@gitlab.epfl.ch:lara/cs206-demos.git.

3. Open it with VSCode (for example using the command code . in cs206-demos).

4. Click on "Import SBT Build":

   

5. Wait while Metals runs bloopInstal:

   

Usage

Normal Scala files

“Normal” Scala files (ending with .scala) must have a @main method. For example, 01-java-threads.scala, the main method is testThreads. You can run it from the command-line, first by entering the sbt shell:

sbt

and then by running:

runMain testThreads

where testThreads is the name of the @main function. This should output something similar to:

sbt:cs206-demos> run testThreads
[info] compiling 1 Scala source to /Users/mbovel/cs206-demos/target/scala-3.2.0/classes ...
[info] running testThreads testThreads
Little threads did not start yet!
ThreadThread-3 has counter 0
ThreadThread-2 has counter 0
ThreadThread-2 has counter 1
Parent thread and children are running!
...

You can also directly run it from VSCode using the run link:

Scala worksheets

Inside src/main/scala, you can create Scala worksheets (files ending with .worksheet.sc). These are special Scala files meant for experimentation where the result of every top-level expression is directly displayed in the IDE. See the official tutorial about Scala worksheets for more details.

We provide sumList.worksheet.sc as an example. If you open it in VSCode, you should see the result of all top-level expressions automatically displayed:

Try to change the code and you should see the results automatically updating!