type 'a conv = [
| `Result of 'a
| `Error of exn * t
]
exception Conv_exn of string * exn
type stack = {
mutable positions : pos list;
mutable stack : t list list;
}
val sexp_of_conv :
('a -> Type.t) ->
[< `Error of exn * t | `Result of 'b ] ->
Type.t
exception Annot_sexp of t