Question

Why following code

def doSomething() = "Something"

var availableRetries: Int = 10

def process(): String = {
  while (true) {
    availableRetries -= 1
    try {
      return doSomething()
    } catch {
      case e: Exception => {
        if (availableRetries < 0) {
          throw e
        }
      }
    }
  }
}

produces following compiler error

error: type mismatch;
 found   : Unit
 required: String
             while (true) {
             ^

?

This works ok in C#. The while loops forever, so it cannot terminate, therefore it cannot result something else than string. Or how to make infinite loop in Scala?

Answer 1

Based on senia, elbowich and dave‘s solutions I used following:

@annotation.tailrec
def retry[T](availableRetries: Int)(action: => T): T = {
  try {
    return action
  } catch {
    case e: Exception if (availableRetries > 0) => { }
  }
  retry(availableRetries - 1)(action)
}

Which can be then used as elbowich and dave’s solutions:

retry(3) {
  // some code
}