From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: weis
Received: (from weis@localhost) by pauillac.inria.fr (8.7.6/8.7.3) id LAA29297 for caml-redistribution; Fri, 30 May 1997 11:52:57 +0200 (MET DST)
Received: from concorde.inria.fr (concorde.inria.fr [192.93.2.39]) by pauillac.inria.fr (8.7.6/8.7.3) with ESMTP id LAA28633 for <caml-list@pauillac.inria.fr>; Fri, 30 May 1997 11:25:03 +0200 (MET DST)
Received: from fermi.cnam.fr (fermi.cnam.fr [163.173.128.60]) by concorde.inria.fr (8.8.5/8.7.3) with ESMTP id LAA11275 for <caml-list@pauillac.inria.fr>; Fri, 30 May 1997 11:25:02 +0200 (MET DST)
Received: from fermi.cnam.fr (fermi.cnam.fr [163.173.128.60])
   by fermi.cnam.fr (8.8.5/jpm-961216)  with SMTP id LAA26628
   ; Fri, 30 May 1997 11:24:21 +0200 (MET DST)
Message-ID: <338E9CC5.41C6@cnam.fr>
Date: Fri, 30 May 1997 11:24:21 +0200
From: Didier Rousseau <Didier.Rousseau@cnam.fr>
Organization: CNAM
X-Mailer: Mozilla 3.01Gold (X11; I; OSF1 V3.2 alpha)
MIME-Version: 1.0
To: mposada@impsat.net.co
CC: caml-list@pauillac.inria.fr
Subject: Re: Type constraints
References: <338DD17B.62C6@impsat.net.co>
Content-Type: text/plain; charset=us-ascii
Content-Transfer-Encoding: 7bit
Sender: weis

bonjour a tous,


Ernesto Posse wrote:
> 
> [My apologies for not including a French Version]
> 
> Hello. I have the folowing problem. I need to define some interrelated
> types as follows:
> 
> type 'a node = {x: 'a; y: t1}
> and t1 = A | B of t1*t1
> and t2 = C | D of (string * t2) node
> 
> The interpreter prints the inferred type:
> 
> type 'a node = { x: 'a; y: t1 } constraint 'a = string * t2
> type t1 = | A | B of t1 * t1
> type t2 = | C | D of (string * t2) node
> ...


une solution est de declarer :

type 'a node = {x: 'a; y: t1}
and t1 = A | B of t1*t1
;;

type t2 = C | D of (string * t2) node | E of bool node
;;




Didier Rousseau