Scala❤Java❤JavaScript

Scala❤Java❤JavaScript.scala

/**
 * Usage:
 *  scalac Main.scala
 *  scala com.example.Main
 */
package com.example

import java.util.function.Function
import javax.script.ScriptEngineManager

object Main extends App {

  def echo(callback: Function[Int, Int]) = callback.apply(2)

  val js =
    """
    var Main = JavaImporter(com.example).Main
    var response = Main.echo(function(two) {
      return 40 + two;
    })
    print(response)
    """

  val engine = new ScriptEngineManager().getEngineByName("nashorn")
  engine.eval(js)

}