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Date: Wed, 4 Mar 2009 15:00:36 +0100
From: Virgile Prevosto <virgile.prevosto@m4x.org>
To: caml-list@yquem.inria.fr
Subject: Re: [Caml-list] recursive records with weak hashtbl
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References: <49AE8296.5040009@mail.ru>
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X-Spam: no; 0.00; recursive:01 hashtbl:01 mutable:01 mutable:01 recursive:01 recursion:01 ocaml:01 2009:98 tutto:98 oggi:98 volta:98 polymorphic:01 beginners:01 caml-list:01 int:01 

Hello,

Le mer. 04 mars 2009 16:31:02 CET,
Vsevolod Fedorov <sevaAtWork@mail.ru> a =E9crit :

> type a
> {
>   id : int ;
>   mutable field1 : string;
>   mutable b : B;
> }
> type b
> {
>     id : int;
>     mutable field2 : string;
>     a_list : Weak-Hashtbl(a);  (* they referenced me *)
> }
>=20
> Is it possible at all?

mutually recursive types are defined like this:
type a =3D { ... }=20
and b =3D { ... }

> Is it possible with A and B declarations in separate files?

not directly, but you can use a polymorphic type to break the recursion.
Assuming that a is defined in a.ml and b in b.ml and that a.ml depends
upon b.ml, you'd have:
- b.ml -
type 'a b =3D { ... a_list: 'a Weak.t }
- a.ml -
type a =3D { ... mutable b: a B.b }

BTW, I'd say that such a topic would be better on the ocaml beginners
list (see reference below)

Regards,
--=20
E tutto per oggi, a la prossima volta.
Virgile