From mboxrd@z Thu Jan 1 00:00:00 1970 Received: (from majordomo@localhost) by pauillac.inria.fr (8.7.6/8.7.3) id SAA16956; Wed, 11 Jul 2001 18:18:11 +0200 (MET DST) X-Authentication-Warning: pauillac.inria.fr: majordomo set sender to owner-caml-list@pauillac.inria.fr using -f Received: (from weis@localhost) by pauillac.inria.fr (8.7.6/8.7.3) id SAA16948 for caml-list@pauillac.inria.fr; Wed, 11 Jul 2001 18:18:10 +0200 (MET DST) Received: from nez-perce.inria.fr (nez-perce.inria.fr [192.93.2.78]) by pauillac.inria.fr (8.7.6/8.7.3) with ESMTP id PAA11927 for ; Wed, 11 Jul 2001 15:52:20 +0200 (MET DST) Received: from hugo.int-evry.fr (hugo.int-evry.fr [157.159.100.81]) by nez-perce.inria.fr (8.11.1/8.10.0) with ESMTP id f6BDqJX19763 for ; Wed, 11 Jul 2001 15:52:19 +0200 (MET DST) Received: from (rinderkn@localhost) by hugo.int-evry.fr (8.8.8/jtpda-5.3) id PAA23738 ; Wed, 11 Jul 2001 15:52:15 +0200 (MET DST) Date: Wed, 11 Jul 2001 15:52:15 +0200 From: Christian RINDERKNECHT To: caml-list@inria.fr Cc: Christian RINDERKNECHT Subject: [Caml-list] Question on typing Message-ID: <20010711155215.B23575@hugo.int-evry.fr> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: 8bit X-Mailer: Mutt 0.95.5i Sender: owner-caml-list@pauillac.inria.fr Precedence: bulk Dear list members, I have a question about typing, but which is not uniquely related to Caml. Could someone tell me the reason why a type variable cannot be used as a type constructor, like in: type 'a t = K of bool 'a;; or type 'a t = {x : 'a 'a};; I suspect non-decidability of type inference (higher-order unification), but I am not an expert of that topic. Also, is type verification undecidable? Is it due to functional types? What happen is there is no (value) functions? Best regards, -- Christian ----------------------------------------------------------------------- Christian Rinderknecht Phone +33 (0)1 60 76 44 43 Institut National des Télécommunications Fax +33 (0)1 60 76 47 11 Département Logiciels Réseaux (LOR) WWW 9, Rue Charles Fourier, F-91011 Évry Cedex ------------------- Bug reports: http://caml.inria.fr/bin/caml-bugs FAQ: http://caml.inria.fr/FAQ/ To unsubscribe, mail caml-list-request@inria.fr Archives: http://caml.inria.fr