[IJ]sbt:root> clean
[success] Total time: 0 s, completed 15.07.2019 16:01:21
[IJ]sbt:root> compile
[info] Updating ...
[info] Done updating.
[info] Compiling 2 Scala sources to /media/data/Projects/sbt_codegen_demo/target/scala-2.13/classes ...
[info] Done compiling.
[success] Total time: 3 s, completed 15.07.2019 16:01:28
[IJ]sbt:root> run
[warn] Multiple main classes detected. Run 'show discoveredMainClasses' to see the list
Multiple main classes detected, select one to run:
[1] App
[2] Runner
[info] Packaging /media/data/Projects/sbt_codegen_demo/target/scala-2.13/root_2.13-0.1.0-SNAPSHOT.jar ...
Enter number: [info] Done packaging.
2
[info] Running Runner
Hello!
[success] Total time: 6 s, completed 15.07.2019 16:01:39
https://www.scala-sbt.org/1.x/docs/Howto-Generating-Files.html
https://github.com/milessabin/shapeless/blob/master/project/Boilerplate.scala
https://github.com/scala/scala/blob/2.13.x/build.sbt#L571-L590