json.scala

sealed abstract class JValue {
  override def toString: String = {
    this match {
      case JString(value)  => String.format("\"%s\"", value)
      case JBool(true)     => "true"
      case JBool(false)    => "false"
      case JNumber(value)  => value.toString
      case JNull()         => "null"
      case JList(values)   => "[" ++ values.map(_.toString).mkString(", ") ++ "]"
      case JObject(values) => "{" ++ values.foldLeft("") { case (prefix, (key, value)) => prefix ++ String.format("\"%s\": %s", key, value) } ++ "}"
    }
  }
}

object JList {
  def apply(list: JValue*) = {
    new JList(list.toList)
  }
}

case class JString(value: String) extends JValue
case class JBool(value: Boolean) extends JValue
case class JNumber(value: Double) extends JValue
case class JNull() extends JValue
case class JList(value: List[JValue]) extends JValue
case class JObject(value: Map[String, JValue]) extends JValue