Question

我坚持使用代码，每当我尝试运行它时，我都会收到错误：

Error:(37, 66) missing parameter type for expanded function
The argument types of an anonymous function must be fully known. (SLS 8.5)
Expected type was: com.bfg.domain.model.RunnerSnap
  def syncPrices(pair: (RunnerSnap, RunnerChange)): RunnerSnap = {

然而，错误消息让我无法知道需要更改什么才能使其正常工作。

  def syncPrices(pair: (RunnerSnap, RunnerChange)): RunnerSnap = {
    case (cache: RunnerSnap, delta: RunnerChange) =>
      val newHc = if (delta.hc.isEmpty) cache.runnerId.handicap else delta.hc
      val id = RunnerId(delta.id, newHc)
      val prices = MarketRunnerPrices(
        atl = syncPriceVolume(cache.prices.atl, delta.atl),
        atb = syncPriceVolume(cache.prices.atb, delta.atb),
        trd = syncPriceVolume(cache.prices.trd, delta.trd),
        spb = syncPriceVolume(cache.prices.spb, delta.spb),
        spl = syncPriceVolume(cache.prices.spl, delta.spl),

        batb = syncLevelPriceVolume(cache.prices.batb, delta.batb),
        batl = syncLevelPriceVolume(cache.prices.batl, delta.batl),
        bdatb = syncLevelPriceVolume(cache.prices.bdatb, delta.bdatb),
        bdatl = syncLevelPriceVolume(cache.prices.bdatl, delta.bdatl),

        spn = if (delta.spn.isEmpty) cache.prices.spn else delta.spn,
        spf = if (delta.hc.isEmpty) cache.prices.spf else delta.spf,
        ltp = if (delta.hc.isEmpty) cache.prices.ltp else delta.ltp,
        tv = if (delta.hc.isEmpty) cache.prices.tv else delta.tv
      )
      RunnerSnap(id, prices)
  }

我的问题是：为什么我会收到此错误以及我需要做什么更改我的代码以使其按预期工作？

Answer 1

您遗失了pair match：

def syncPrices(pair: (RunnerSnap, RunnerChange)): RunnerSnap = pair match {
  case (cache: RunnerSnap, delta: RunnerChange) =>
    ...
}

追踪“扩展函数的缺失参数类型”

1 个答案: