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 FAA19702; Tue, 12 Aug 2003 05:24:49 +0200 (MET DST)
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 FAA26728 for <caml-list@pauillac.inria.fr>; Tue, 12 Aug 2003 05:24:48 +0200 (MET DST)
Received: from kurims.kurims.kyoto-u.ac.jp (kurims.kurims.kyoto-u.ac.jp [130.54.16.1])
	by concorde.inria.fr (8.11.1/8.11.1) with ESMTP id h7C3Okf29714
	for <caml-list@inria.fr>; Tue, 12 Aug 2003 05:24:46 +0200 (MET DST)
Received: from localhost (suiren.kurims.kyoto-u.ac.jp [130.54.16.25])
	by kurims.kurims.kyoto-u.ac.jp (8.9.3p2/3.7W) with ESMTP id MAA19923;
	Tue, 12 Aug 2003 12:24:38 +0900 (JST)
To: skaller@ozemail.com.au
Cc: caml-list@inria.fr
Subject: Re: [Caml-list] tpyping question
In-Reply-To: <20030811114615Y.garrigue@kurims.kyoto-u.ac.jp>
References: <1060564412.7474.11.camel@localhost.localdomain>
	<20030811114615Y.garrigue@kurims.kyoto-u.ac.jp>
X-Mailer: Mew version 1.94.2 on Emacs 21.2 / Mule 5.0 (SAKAKI)
Mime-Version: 1.0
Content-Type: Text/Plain; charset=us-ascii
Content-Transfer-Encoding: 7bit
Message-Id: <20030812122438E.garrigue@kurims.kyoto-u.ac.jp>
Date: Tue, 12 Aug 2003 12:24:38 +0900
From: Jacques Garrigue <garrigue@kurims.kyoto-u.ac.jp>
X-Dispatcher: imput version 20000228(IM140)
X-Loop: caml-list@inria.fr
X-Spam: no; 0.00; jacques:01 caml-list:01 ozemail:01 compiles:01 bug:01 val:01 or-patterns:01 subsumed:01 superfluous:01 int:01 garrigue:01 match:02 float:02 let:04 meaningful:04 
Sender: owner-caml-list@pauillac.inria.fr
Precedence: bulk

> From: skaller <skaller@ozemail.com.au>
> 
> > type x = [`A | `B of int | `V of float];;
> > let g (a:x) = a;;
> > let f a = match a with
> > | `A -> g a
> > (* | `B _ *) | _ -> g a;;
> > 
> > Compiles fine, but gives an error if the comments are
> > removed.
> 
> Indeed, there seems to be a bug here, since the non-commented version
> should be equivalent to
> 
> # let f a = match a with
>   | `A ->  g a
>   | `B _ -> g a
>   | _ -> g a;;
> val f : x -> x = <fun>

This is now fixed in CVS.
Redundant cases of or-patterns (i.e. subsumed by another case) are now
ignored in exhaustivity check.
This confirms what I said before: this was only a problem with
redundant patterns. These are completely superfluous now, as pattern
matching does not respect the order of patterns in or-patterns, but
this may indeed change in the future:
  let f = function
    | `A -> g `A
    | `B a | a -> g a
could become meaningful.

-------------------
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