for BASE talk

Dynamic.scala

import scala.util.DynamicVariable

class Workspace {
  def run(s: String) { println(s) }
  def report(s: String) = 10
  def dispose() { println("disposed") }
}

def expect[T](expected: T)(actual: T) {
  assert(expected == actual, actual.toString)
}

val workspace =
  new DynamicVariable[Workspace](null)
val run = workspace.value.run(_)
val report = workspace.value.report(_)

def testLanguage(name: String)
                (body: => Unit) {
  val w = new Workspace
  try workspace.withValue(w) { body }
  finally w.dispose()
}

testLanguage("create and count") {
  run("create-turtles 10")
  expect(10)(
    report("count turtles"))
}