Re: [Caml-list] Polymorphic recursion

["Roland Zumkeller" <roland.zumkeller@gmail.com>]

On 04/04/07, Alain Frisch <Alain.Frisch@inria.fr> wrote:
> The fact that something is well-typed in Coq does not mean that you can
> just translate it to OCaml by adding a few Obj.magic to make the
> type-checker happy.

As I understand Pierre Letouzey's PhD thesis explains how this can be
done. Your example couldn't result from translating a Coq term, since
"String.copy", "ref", and "Gc.major" are not part of its formalism (a
flavour of lambda calculus with inductive types).

> let () =
>   let x = if ("a" = "b") then Obj.magic 0 else String.copy "abc" in
>   for i = 0 to 100000 do ignore (ref [1]) done;
>   Gc.major ();
>   print_endline x

> This code compiled with ocamlopt produces a segfault on my machine.

On my machine it prints "$d$d$d$d$d$d$d$d$d$d$d$d$d$d$d" and when
compiled with ocamlc "abc". Is this a bug?

Roland

-- 
http://www.lix.polytechnique.fr/~zumkeller/