Scala - complex conditional pattern matching

Question

I have a statement I want to express, that in C pseudo-code would look like this:

switch(foo):
    case(1)
        if(x > y) {
            if (z == true)
                doSomething()
            }
            else {
                doSomethingElse()
            }
        return doSomethingElseEntirely()

    case(2)
        essentially more of the same

Is a nice way possible with the scala pattern matching syntax?

Solution

If you want to handle multiple conditions in a single match statement, you can also use guards that allow you to specify additional conditions for a case:

foo match {    
  case 1 if x > y && z => doSomething()
  case 1 if x > y => doSomethingElse()
  case 1 => doSomethingElseEntirely()
  case 2 => ... 
}

Comments

[Rex Kerr]

This doesn't actually match what the OP wrote. The control flow is different; on x>y&&z, the OP executes doSomething(), return doSomethingElseEntirely(), while yours returns doSomething() alone.

[Tomas Petricek]

@Rex - Good point, thanks. I didn't quite get it because OP's code is missing some opening and closing curly braces. Anyway, it should be easy to fix the body accordingly.

[Alexander Aleksandrovič Klimov]

To me, this doesn't make it clear the x > y test is common to the first two branches. There's nothing inherently wrong with if/then/else and in this case, it's clearer (IMO).

[Vincenzo Maggio]

@Paul I agree, but it was the OP to ask for this kind of solution! :)

[Valentin Tihomirov]

I fail to use guards in the exception handling

[Geoffrey Wiseman]

I know this is old, but I will say that in some ways I prefer the pattern match -- it lays out that there are three paths and that the paths each have a set of necessary conditions. It emphasizes the branch rather than the common elements of the conditions, which in some cases might be clearer.