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 KAA20188 for caml-redistribution; Mon, 11 Jan 1999 10:19:01 +0100 (MET)
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 LAA03921 for <caml-list@pauillac.inria.fr>; Sun, 10 Jan 1999 11:53:42 +0100 (MET)
Received: from landsraad.net (caladan.arrakis.es [195.5.65.34])
	by concorde.inria.fr (8.8.7/8.8.7) with ESMTP id LAA26049
	for <caml-list@pauillac.inria.fr>; Sun, 10 Jan 1999 11:53:41 +0100 (MET)
Received: from ind-cr.uclm.es (jjgarcia@ij-207.arrakis.es [195.5.79.207])
	by landsraad.net (8.9.1a/8.9.1) with ESMTP id LAA23519
	for <caml-list@pauillac.inria.fr>; Sun, 10 Jan 1999 11:55:34 +0100 (MET)
Sender: weis
Message-ID: <369885D1.1C8A1269@ind-cr.uclm.es>
Date: Sun, 10 Jan 1999 11:49:53 +0100
From: Juan Jose Garcia Ripoll <jjgarcia@ind-cr.uclm.es>
X-Mailer: Mozilla 4.05 [en] (X11; I; Linux 2.0.34 i686)
MIME-Version: 1.0
To: Caml list <caml-list@pauillac.inria.fr>
Subject: Map is not tail recursive
Content-Type: text/plain; charset=us-ascii
Content-Transfer-Encoding: 7bit

Hi,

I've had a look at the List package and it seems that it is not properly
tail recursive. Even more, for medium to large lists it exhausts the
stack. I would suggest either recoding it as

let map f a =
   let domap f done todo =
      match todo with
         [] -> List.reverse done
       | (x::xs) -> domap (f x)::done xs
   in domap f [] a

Another possibility would be to introduce destructive operations such as
Scheme's setcdr! and setcar!. This would eliminate the need of using
List.reverse, at the cost of introducing some imperative style.

Please excuse any mistake -- I'm quite new to this language.

Regards

	Juanjo