REPL

The repl command starts a Scala REPL, which lets you interactively run your code and inspect its results:

scala-cli repl
# scala> println("Hello Scala")
# Hello Scala
#
# scala> :exit

Scala CLI by default uses the normal Scala REPL.

If you prefer to use the Ammonite REPL, specify --amm to launch it rather than the default REPL:

scala-cli repl --amm
# Loading...
# Welcome to the Ammonite Repl 2.4.0-23-76673f7f (Scala 3.0.2 Java 11.0.11)
# @ println("Hello ammonite")
# Hello ammonite
# @ exit
# Bye!

The repl command accepts the same arguments as the compile command. It first compiles any provided sources, and then exposes those results and any provided dependencies to the REPL session:

mylibrary/Messages.scala

package mylibrary

object Messages {
  def message = "Hello"
  def print(): Unit = println(message)
}

scala-cli repl mylibrary/Messages.scala
# Compiling project (Scala 3.0.2, JVM)
# Compiled project (Scala 3.0.2, JVM)
# scala> import mylibrary._
#
# scala> Messages.print()
# Hello
#
# scala> :quit