feat(Error): add Error.result/try_

src/util/Error.ml

@@ -8,3 +8,7 @@ let () =
     | _ -> None)
 
 let errorf msg = Fmt.ksprintf msg ~f:(fun s -> raise (Error s))
+
+type nonrec 'a result = ('a, string) result
+
+let try_ f = try Ok (f ()) with Error s -> Error s

src/util/Error.mli

@@ -2,3 +2,7 @@ exception Error of string
 
 val errorf : ('a, Format.formatter, unit, 'b) format4 -> 'a
 (** @raise Error when called *)
+
+type nonrec 'a result = ('a, string) result
+
+val try_ : (unit -> 'a) -> 'a result