How to make an enum variant have a field which can be another enum variant?

1

I am trying to see if I can create an enum, whereby I have an enum, with 3 variants, where the last one is a struct that has a field which can be one of the other two enum variants. I.e.

enum A {
    A1,
    A2,
    A3 {
        field: A // This can be either A1 or A2
    }
}

When doing this I get the error saying that A has infinite size, however I was wondering if there was a way to say that although the field must be a variant, it can only be of type A1 or A2, which wouldnt result in an infinite size?

Thanks
Karl

2

There is not currently any way to subset an enum. What you should do instead is split it up into the parts you want to work with:

enum OneTwo {
    A1,
    A2,
}

enum A {
    A12(OneTwo),
    A3 {
        field: OneTwo
    },
}

This A has the same set of possible values that you wanted.

(Of course, give them better names that make sense in context.)

5 Likes
3

@kpreid thank you very much for your swift reply!!