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 WAA13027; Thu, 5 Dec 2002 22:53:40 +0100 (MET)
X-Authentication-Warning: pauillac.inria.fr: majordomo set sender to owner-caml-list@pauillac.inria.fr using -f
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 WAA13121 for <caml-list@pauillac.inria.fr>; Thu, 5 Dec 2002 22:53:39 +0100 (MET)
Received: from slave-dog.naughtydog.com (naughtydog200.brandx.net [209.55.75.200])
	by concorde.inria.fr (8.11.1/8.11.1) with SMTP id gB5LrbX08335
	for <caml-list@inria.fr>; Thu, 5 Dec 2002 22:53:38 +0100 (MET)
Received: from SMTP agent by mail gateway 
 Thu, 05 Dec 2002 13:55:48 -0800
Received: from katn-dog (engstad@katn-dog.naughtydog.com [10.0.0.90])
	by slave-dog.naughtydog.com (SGI-8.9.3/8.9.3) with ESMTP id NAA40182;
	Thu, 5 Dec 2002 13:55:43 -0800 (PST)
Content-Type: text/plain;
  charset="iso-8859-1"
From: Pal-Kristian Engstad <engstad@naughtydog.com>
Organization: Naughty Dog, Inc.
To: Oleg <oleg_inconnu@myrealbox.com>,
        Pal-Kristian Engstad <engstad@slave-dog.naughtydog.com>,
        caml-list@inria.fr
Subject: Re: [Caml-list] Why is (@) written in O'Caml?
Date: Thu, 5 Dec 2002 13:55:41 -0800
User-Agent: KMail/1.4.3
References: <200212051547.09337.oleg_inconnu@myrealbox.com> <200212051316.08952.engstad@naughtydog.com> <200212051624.37333.oleg_inconnu@myrealbox.com>
In-Reply-To: <200212051624.37333.oleg_inconnu@myrealbox.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Message-Id: <200212051355.41175.engstad@naughtydog.com>
Sender: owner-caml-list@pauillac.inria.fr
Precedence: bulk

On Thursday 05 December 2002 01:24 pm, Oleg wrote:
> On Thursday 05 December 2002 04:16 pm, Pal-Kristian Engstad wrote:
> > But, that is _exactly_ what the function above does!
>
> It's not about *what* it does, but *how* (@) does it. (@) is recursive and
> not tail-recursive.

Okey - I see where you're coming from. Since we know that we're creating a new 
copy of a list, we know there will be references to it elsewhere, hence we 
may see it as a mutable list and do something like:

struct cell { value *hd; cell* tl; };
newlist = nil;
prev = nil;
list = l1;
/* copy l1 */
while (list != nil) {
   pnew = alloc(list);           /* Allocate new cell. */
   if (!newlist) newlist = pnew; /* Mark first cell. */
   pnew->hd = list->hd;          /* Copy data at cell. */
   pnew->tl = nil;               /* Init to nil. */
   if (prev) prev->tl = pnew;    /* Link previous cell to this. */
   prev = pnew;                  /* Update previous. */
   list = list->tl;              /* Get next l1 cell. */
}
if (prev) {
   prev->tl = l2;
   return newlist;
}
else {
   return l2;
}

Is that what you mean?

PKE.

-------------------
To unsubscribe, mail caml-list-request@inria.fr Archives: http://caml.inria.fr
Bug reports: http://caml.inria.fr/bin/caml-bugs FAQ: http://caml.inria.fr/FAQ/
Beginner's list: http://groups.yahoo.com/group/ocaml_beginners