I'm wondering how can I use multiple type pattern matching. I have:
abstract class MyAbstract
case class MyFirst extends MyAbstract
case class MySecond extends MyAbstract
case class MyThird extends MyAbstract // shouldn't be matched and shouldn't call doSomething()
val x: MyAbstract = MyFirst
x match {
case a: MyFirst => doSomething()
case b: MySecond => doSomething()
case _ => doSomethingElse()
}
So I'd like to write something like:
x match {
case a @ (MyFirst | MySecond) => doSomething()
case _ => doSomethingElse()
}
I saw similar construction in some tutorial, but it gives me error:
pattern type is incompatible with expected type;
[error] found : object MyFirst
[error] required: MyAbstract
So is there a way to define few different types in on case clause? I think it would make code prettier. As if I will have 5 of them, I will write same code 5 times (calling doSomething()).
Thanks in advance!
You are missing the parenthesis for your case classes.
Case classes without parameter lists are deprecated.
Try this:
abstract class MyAbstract
case class MyFirst() extends MyAbstract
case class MySecond() extends MyAbstract
val x: MyAbstract = MyFirst()
x match {
case aOrB @ (MyFirst() | MySecond()) => doSomething(aOrB)
case _ => doSomethingElse()
}
If you have too many params for your case classes and don't like having to write long Foo(_,_,..)
patterns, then maybe:
x match {
case aOrB @ (_:MyFirst | _:MySecond) => doSomething(aOrB)
case _ => doSomethingElse()
}
Or just:
x match {
case _:MyFirst | _:MySecond => doSomething(x) // just use x instead of aOrB
case _ => doSomethingElse(x)
}
But perhaps you just wanted singleton case objects?
abstract class MyAbstract
case object MyFirst extends MyAbstract
case object MySecond extends MyAbstract
val x: MyAbstract = MyFirst
x match {
case aOrB @ (MyFirst | MySecond) => doSomething()
case _ => doSomethingElse()
}