gistfile1.scala

  sealed trait Value{ val value: Any }
  case class Closure[V](l:Lambda, env:Env)    extends Value{ val value = this }
  case class ObjectValue(value:Any)           extends Value
  case class DynamicValue(value: () => Value) extends Value
  case class BuiltinFunction(name: Symbol, eval: (List[Expr], Env) => Value) extends Value {
    val value = this
  }