Thank you for those links. The first one is especially clear. However, this is just not something that I typically perceive as a problem. For example in the bo

Thank you for those links. The first one is especially clear. However, this is just not something that I typically perceive as a problem. For example in the book that I mentioned above, I didn't feel the need to use it at all. I just added the fields or the functions that were required. In the first link you provided, the OCaml code seems to use unions as well (I don't know the language). I assume OCaml checks for exhaustive matching, so it seems extremely straight forward to extend this code. On the other hand I have absolutely no issues with a big switch case in a more simple language. I just had a look at the code I wrote quite a while ago and it looks fine.