Embedded Scala REPL Interpreter example for 2.10

Question

Please give a code example of how to create an embedded Scala REPL interpreter programmatically, that works in Scala 2.10. (I added this Q&A after spending hours combing

Answer 1

Based on Ben's excellent answer, below is a helper class to ease starting the interpreter. Usage:

Repl.run(("e", "Double", 2.71828), ("pi", "Double", 3.1415))

It automatically detects when you're running from SBT and accommodates.

Repl.scala:

import scala.tools.nsc.interpreter.ILoop
import scala.tools.nsc.Settings
import java.io.CharArrayWriter
import java.io.PrintWriter

object Repl {

  def run(params: (String, String, Any)*) {

    def repl = new ILoop {
      override def loop(): Unit = {
        params.foreach(p => intp.bind(p._1, p._2, p._3))
        super.loop()
      }
    }

    val settings = new Settings
    settings.Yreplsync.value = true

    // Different settings needed when running from SBT or normally
    if (isRunFromSBT) {
      settings.embeddedDefaults[Repl.type]
    } else {
      settings.usejavacp.value = true
    }

    repl.process(settings)
  }

  def isRunFromSBT = {
    val c = new CharArrayWriter()
    new Exception().printStackTrace(new PrintWriter(c))
    c.toString().contains("at sbt.")
  }

}