michaeldiamant

  object E1 {
    // Encoding a 1:1 command to event example
    sealed trait Event
    case class E1(i: Int) extends Event
    case class E2() extends Event
    sealed trait Intent[Z <: Event] {
      type Out = Z
    }
    case class C1(id: Int) extends Intent[E1]
    case class C2(id: Int) extends Intent[E1]

michaeldiamant

[michael@dca-infra01 ansible]$ cat /home/michael/ntoggle/ansible/roles/ntoggle.helix-service/tasks/required_vars.yml - name: check required variables are defined
  fail: msg="Variable '{{ item }}' is undefined"
  when: item is not defined
  with_items:
    - foo
    - bar

- fail: msg="foo"
  when: foo is not defined
  

michaeldiamant

trait Usd

trait Eur

trait ProfitCalculator[T] {

  def calculateProfit(executionPrice: BigDecimal @@ T, requestedPrice: BigDecimal @@ T): BigDecimal @@ T =
    tag(executionPrice - requestedPrice)
}

michaeldiamant

case class UsdPrice(value: BigDecimal) {

  def +(p: UsdPrice) = UsdPrice(value + p.value)

  def -(p: UsdPrice) = UsdPrice(value - p.value)
}

case class EurPrice(value: BigDecimal) {

  def +(p: EurPrice) = EurPrice(value + p.value)

michaeldiamant

trait ExtensibleTradeExecutionProcessor extends TradeExecutionProcessor {

  val requestedTradeRepository: RequestedTradeRepository
  val priceMutators: Set[(RequestedTrade, BigDecimal) => BigDecimal]

  def process(requestId: String, executionPrice: BigDecimal): Option[ExecutedTrade] =
    for {
      requestedTrade <- requestedTradeRepository.findById(requestId)
      reportedPrice <- priceMutators.foldLeft(executionPrice)((price, mutator) => mutator(requestedTrade, price)).some
    } yield

michaeldiamant

trait ComplectingTradeExecutionProcessor extends TradeExecutionProcessor with MarkupApplicator {

  val requestedTradeRepository: RequestedTradeRepository
  val markingUpSymbol: String
  val symbolMarkup: BigDecimal
  val markupVolumeThreshold: Long
  val volumeMarkup: BigDecimal

  def process(requestId: String, executionPrice: BigDecimal): Option[ExecutedTrade] =
    requestedTradeRepository.findById(requestId)

michaeldiamant

trait MonadicStyleNewOrderResolver extends NewOrderResolutionErrors {

  val symbolDao: SymbolDao
  val marketTakerDao: MarketTakerDao
  val marketMakerDao: MarketMakerDao

  def resolve(order: NewOrder): Validation[String, ResolvedNewOrder] =
    for {
      symbol <- symbolDao.findByName(order.symbolName)
        .toSuccess(UnknownSymbol)

michaeldiamant

trait JavaStyleNewOrderResolver extends NewOrderResolutionErrors {

  val symbolDao: SymbolDao
  val marketTakerDao: MarketTakerDao
  val marketMakerDao: MarketMakerDao

  def resolve(order: NewOrder): Either[String, ResolvedNewOrder] = {
    val symbol = symbolDao.findByName(order.symbolName)
    if (symbol.isEmpty) {
      return Left(UnknownSymbol)