scalamonadsfor-comprehension

for..else for Option types in Scala?

Suppose I have two Options and, if both are Some, execute one code path, and if note, execute another. I'd like to do something like

for (x <- xMaybe; y <- yMaybe) {
  // do something
}
else {
  // either x or y were None, handle this
}

Outside of if statements or pattern matching (which might not scale if I had more than two options), is there a better way of handling this?

Solution

  • Very close to your syntax proposal by using yield to wrap the for output in an Option:

    val result = { 
  for (x <- xMaybe; y <- yMaybe) yield {
    // do something
  }
} getOrElse {
  // either x or y were None, handle this
}

    The getOrElse block is executed only if one or both options are None.