Converting variants with only constant constructors to integers

["Török Edwin" <edwintorok@gmail.com>]

Hi,

What is the recommended way to convert a variant that has only constant
constructors to an integer? (an integer that is unique for each constant
constructor, preferably sequential in the order in which they are declared).

I found the following two possibilities, but I am not sure if these are
guaranteed to return the same results for future versions of OCaml or not:

let int_of_constant_variant a : int = Hashtbl.hash a;;
let int_of_constant_variant a : int =
 let r = Obj.repr a in
  assert (Obj.is_int r);
  (Obj.magic r : int);;

for 'type t = A | C | B', both of these functions return 0,1, and 2 for
A,C, and B respectively.

Best regards,
--Edwin