Order in type definitions, output_value on abstract values

Order in type definitions, output_value on abstract values

[Pascal Brisset]

Two non related questions about Ocaml 1.05, one about type
signatures and one about a low-level implementation detail:

 - Why the order of labels and constructors in type definition is
relevant ?

# module M : sig type t = A | B end =
    struct type t = B | A end;;
Signature mismatch:
...
# module M : sig type t = {a : int; b : int} end =
    struct type t = {b : int; a : int} end;;
Signature mismatch:
...

 - Why is it not possible to output_value an abstract value if it is atomic ?

# output_value stdout (Hashtbl.create 1);;
¦¾ C@- : unit = ()
# output_value stdout stdout;;
Uncaught exception: Invalid_argument("output_value: abstract value")

--Pascal Brisset