case object & {
    def unapply[T](t : T) = Some(t, t)
  }


case object ParamA {
    def unapply(jsonStr: String) : Option[String] = {
      // If param A found in json return a Some(...) else None
    ???
    }
  }
  case object ParamB {
    def unapply(jsonStr: String) : Option[String] = {
      // If param B found in json return a Some(...) else None
      ???
    }
  }
  case object ParamC {
    def unapply(jsonStr: String) : Option[String] = {
      // If param C found in json return a Some(...) else None
      ???
    }
  }

val jsonStr = "..." // A Json string
    jsonStr match {
      case ParamA(a) & ParamB(b) => {
        // Got a and b. Now do something with it
      }
      case _ => {

      }
    }

val jsonStr = "..." // A Json string
    jsonStr match {
      case ParamA(a) & ParamB(b) & Optional(ParamC(c)) /* Is this possible? */ => {
        // Got a and b and an optional c. Now do something with it
      }
      case _ => {

      }
    }