Question

当我运行以下代码时，我收到一些错误：

Error:(15, 25) missing parameter type for expanded function
The argument types of an anonymous function must be fully known. (SLS 8.5)
Expected type was: ?
  testFuture onComplete({
                    ^

代码：

object TestFuture extends App{

val exe = ExecutionContext.fromExecutor(Executors.newCachedThreadPool())

testFuture onComplete({
case Success((str,i)) =>{
  println(str,i)
}
case Failure(e) =>{
  e.printStackTrace()
}})(exe)


println(Runtime.getRuntime.availableProcessors())
Thread.sleep(2000)

def testFuture:Future[(String,Int)] = Future[(String,Int)] {
  Thread.sleep(1000)
  ("oh my sky",12)
}(exe)
}

当我装饰＆＃39; val exe＆＃39;与隐含的＆＃39;并且在没有明确使用＆＃39; exe＆＃39;之前调用currying函数。像下面的代码，它是正确的。你能告诉我为什么吗？

object TestFuture extends App{
implicit val exe = ExecutionContext.fromExecutor(Executors.newCachedThreadPool())

testFuture onComplete({
case Success((str,i)) =>{
  println(str,i)
}
case Failure(e) =>{
  e.printStackTrace()
}})


println(Runtime.getRuntime.availableProcessors())
Thread.sleep(2000)

def testFuture:Future[(String,Int)] = Future[(String,Int)] {
  Thread.sleep(1000)
  ("oh my sky",12)
}
}

Answer 1

我猜，中缀方法调用不支持多个参数列表。尝试使用点符号：

testFuture.onComplete{
  case Success((str,i)) =>
    println(s"$str, $i")
  case Failure(e) =>
    e.printStackTrace()
}(exe)

Scala，Currying on partial function parameter和implicit parameter

1 个答案: