I have this for mine:
struct Ag { tag :String, //like "Option.None" data:Vec<Value> //The data inside, if any }
https://hackage.haskell.org/package/rel8-1.1.0.0/docs/src/Re...
You have a bool which specifies whether it's left or right, and then two payloads, one for left and one for right.
I have this for mine: