Scala Toolkit

Scala Toolkit is an ongoing effort by Scala Center and VirtusLab to compose a set of approachable libraries to solve everyday problems.

You can easily add it to your Scala CLI project with the --toolkit option:

UseOsLib.sc

println(os.pwd)

scala-cli UseOsLib.sc --toolkit latest

Similarly, you can achieve the same with the using toolkit directive:

//> using toolkit latest
@main def printPwd: Unit = println(os.pwd)

Scala Toolkit and tests

Adding Scala Toolkit to your project effectively adds 2 dependencies to your classpath:

• org.scala-lang:toolkit:<version> for your main scope (usable everywhere in the project);
• org.scala-lang:toolkit-test:<version> for your test scope (usable only in tests).

toolkit-test includes a batch of libraries only relevant for testing (like i.e. munit), which you probably don't want on your main scope class path (which is why Scala CLI won't put it there). And so, you can use it like this:

Something.test.scala

//> using toolkit latest
class Something extends munit.FunSuite {
  test("foo") {
    assert(true)
  }
}

scala-cli test Something.test.scala

Also, in case you only want Scala Toolkit to be added to the test scope (and not for the main scope in any capacity), you can always use the using test.toolkit directive.

project.scala

//> using test.toolkit latest

Another.test.scala

class Another extends munit.FunSuite {
  test("foo") {
    assert(os.pwd.last.nonEmpty)
  }
}

scala-cli test Another.test.scala project.scala

More details about test scope directives can be found in the using directives guide.

Other toolkits

Scala CLI also supports adding other toolkits to your project in a similar manner. Those have to follow the same structure of 2 dependencies with the names toolkit and toolkit-test. To do so, you have to explicitly pass the organisation the toolkit was released under (or an alias if defined).

For example, to add the Typelevel Toolkit to your project, you can pass it with the --toolkit option:

UseTypelevel.scala

import cats.effect.*
import fs2.io.file.Files

object Hello extends IOApp.Simple {
  def run = Files[IO].currentWorkingDirectory.flatMap { cwd =>
    IO.println(cwd.toString)
  }
}

scala-cli UseTypelevel.scala --toolkit org.typelevel:latest
scala-cli UseTypelevel.scala --toolkit typelevel:latest # typelevel has a shorter alias defined

Similarly, you can achieve the same with the using toolkit directive:

//> using toolkit org.typelevel:latest

import cats.effect.*
import fs2.io.file.Files

object Hello extends IOApp.Simple {
  def run = Files[IO].currentWorkingDirectory.flatMap { cwd =>
    IO.println(cwd.toString)
  }
}

Or with the alias:

//> using toolkit typelevel:latest

import cats.effect.*
import fs2.io.file.Files

object Hello extends IOApp.Simple {
  def run = Files[IO].currentWorkingDirectory.flatMap { cwd =>
    IO.println(cwd.toString)
  }
}