inspired by Pythons: >> import pdb;pdb.set_trace() I hacked something similar to have breakpoints in Scala 2.9 && 2.10 by typing: import break._;break[someClass]("MainObject" -> MainObject)

scala.breakpoint.scala

import scala.tools.nsc.interpreter._
import scala.tools.nsc.Settings

//USAGE EXAMPLE: import break._;break[someClass]("MainObject" -> MainObject)

object break{
  def echo(x: Any) = Console.println(x)

  def break[T: Manifest](args: NamedParam*) = {
    
    val repl = new ILoop
    repl.settings = new Settings(echo)
    repl.settings.embeddedDefaults[T]
    repl.createInterpreter()
    repl.in = SimpleReader()

    // repl.bind("p", "Array[page]", MainObject.pages)
    val params = args.toList
    println(args)
    params foreach (p => repl.bind(p.name, p.tpe, p.value))

    var k = ""
    while( k !="q"){
      k = Console.readLine()
      repl.interpret(k)
    }
  }
}