Foldable pattern

/**
 * The catamorphism for the JSON value data type.
 */
final def fold[X](
  jsonNull: => X,
  jsonBoolean: Boolean => X,
  jsonNumber: JsonNumber => X,
  jsonString: String => X,
  jsonArray: Vector[Json] => X,
  jsonObject: JsonObject => X
): X = this match {
  case JNull       => jsonNull
  case JBoolean(b) => jsonBoolean(b)
  case JNumber(n)  => jsonNumber(n)
  case JString(s)  => jsonString(s)
  case JArray(a)   => jsonArray(a)
  case JObject(o)  => jsonObject(o)
}

//usage:
json.fold(
  None,
  boolValue => Some(s"This is boolean: $boolValue"),
  numberValue => Some(s"This is integer: ${numberValue.toInt}"),
  _ => None,
  _ => None,
  _ => None,
)