Switch Expression Block

[TonyValenti]

Can you use blocks in switch expressions?
ie:

var ret = input switch {
  _ => {
    return default;
  },
};

I feel like this should work but it doesnt seem to.

[iam3yal]

@TonyValenti It was suggested before, in fact I suggested it as well back then when they designed it and the response by Neal Gafter was to use local functions.

[HaloFour]

From what I recall the interest was in exploring sequence expressions in general since they would solve this case and others, but if that proved too problematic to explore as a specific syntax for switch expressions. IMO, given that the most likely use case for it would be with switch I'd be in favor of ditching the larger sequence expression exploration. I like the way the expression blocks with in Java, they use the yield keyword.

[333fred]

Duplicate of #3037.

[TonyValenti]

I think I need to clarify something here.

In:

var ret = input switch {
  _ => {
    return default;
  },
};

I intend the return statement to mean "set the result for this branch of the switch", not "return from the method".
It would have the same result as (although this might not be valid code):

var ret = input switch {
  _ => () => {
    return default;
  }(),
};

[333fred]

Yes, I understand that. That's why I linked the issue I did, as this is a duplicate (though I used break instead of return in my version).

[Unknown6656]

Yes please. Currently, I have to resort to solutions like:

public static T Do<T>(Func<T> f) => f();

int x = ....;
int y = x switch {
    < 3 => 42,
    > 10 => 69,
    _ => Do<int>(() =>
    {
          // logic goes here
          return -1;
    }),
}

or even worse (readability-wise):

int x = ....;
int y = x switch {
    < 3 => 42,
    > 10 => 69,
    _ => new Func<int>(() =>
    {
          // logic goes here
          return -1;
    })(),
}