From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: Stefan Monnier Newsgroups: gmane.emacs.bugs Subject: bug#9222: 23.3.50; "void" is not "typeless" (but thanks for the koan!) Date: Sat, 10 Sep 2011 23:25:10 -0400 Message-ID: References: <87sjpkc5zm.fsf@sc3d.org> NNTP-Posting-Host: lo.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-Trace: dough.gmane.org 1315711560 32400 80.91.229.12 (11 Sep 2011 03:26:00 GMT) X-Complaints-To: usenet@dough.gmane.org NNTP-Posting-Date: Sun, 11 Sep 2011 03:26:00 +0000 (UTC) Cc: Reuben Thomas , 9222@debbugs.gnu.org To: Lars Magne Ingebrigtsen Original-X-From: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane.org@gnu.org Sun Sep 11 05:25:56 2011 Return-path: Envelope-to: geb-bug-gnu-emacs@m.gmane.org Original-Received: from lists.gnu.org ([140.186.70.17]) by lo.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1R2ag6-000639-HU for geb-bug-gnu-emacs@m.gmane.org; Sun, 11 Sep 2011 05:25:54 +0200 Original-Received: from localhost ([::1]:48413 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1R2ag5-0004xE-R3 for geb-bug-gnu-emacs@m.gmane.org; Sat, 10 Sep 2011 23:25:53 -0400 Original-Received: from eggs.gnu.org ([140.186.70.92]:57382) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1R2ag3-0004x6-EO for bug-gnu-emacs@gnu.org; Sat, 10 Sep 2011 23:25:52 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1R2ag2-0001Vp-Dm for bug-gnu-emacs@gnu.org; Sat, 10 Sep 2011 23:25:51 -0400 Original-Received: from debbugs.gnu.org ([140.186.70.43]:34093) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1R2ag2-0001Vl-A0 for bug-gnu-emacs@gnu.org; Sat, 10 Sep 2011 23:25:50 -0400 Original-Received: from Debian-debbugs by debbugs.gnu.org with local (Exim 4.69) (envelope-from ) id 1R2ak7-00025e-7h; Sat, 10 Sep 2011 23:30:03 -0400 X-Loop: help-debbugs@gnu.org Resent-From: Stefan Monnier Original-Sender: debbugs-submit-bounces@debbugs.gnu.org Resent-To: owner@debbugs.gnu.org Resent-CC: bug-gnu-emacs@gnu.org Resent-Date: Sun, 11 Sep 2011 03:30:03 +0000 Resent-Message-ID: Resent-Sender: help-debbugs@gnu.org X-GNU-PR-Message: followup 9222 X-GNU-PR-Package: emacs X-GNU-PR-Keywords: Original-Received: via spool by 9222-submit@debbugs.gnu.org id=B9222.13157117657968 (code B ref 9222); Sun, 11 Sep 2011 03:30:03 +0000 Original-Received: (at 9222) by debbugs.gnu.org; 11 Sep 2011 03:29:25 +0000 Original-Received: from localhost ([127.0.0.1] helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.69) (envelope-from ) id 1R2ajV-00024T-0b for submit@debbugs.gnu.org; Sat, 10 Sep 2011 23:29:25 -0400 Original-Received: from ironport2-out.teksavvy.com ([206.248.154.183] helo=ironport2-out.pppoe.ca) by debbugs.gnu.org with esmtp (Exim 4.69) (envelope-from ) id 1R2ajT-00024N-WB for 9222@debbugs.gnu.org; Sat, 10 Sep 2011 23:29:24 -0400 X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: AhkGAKUpbE5FxK3+/2dsb2JhbABBhFWdBgOGOnmBUgEBBAEjMxESEAsaAhgOAgIUGA0kiAqkCZAqgSyEMYERBKAyhEM X-IronPort-AV: E=Sophos;i="4.68,362,1312171200"; d="scan'208";a="135615936" Original-Received: from 69-196-173-254.dsl.teksavvy.com (HELO ceviche.home) ([69.196.173.254]) by ironport2-out.pppoe.ca with ESMTP/TLS/ADH-AES256-SHA; 10 Sep 2011 23:25:10 -0400 Original-Received: by ceviche.home (Postfix, from userid 20848) id 1C22E663AA; Sat, 10 Sep 2011 23:25:10 -0400 (EDT) In-Reply-To: (Lars Magne Ingebrigtsen's message of "Sun, 11 Sep 2011 03:59:39 +0200") User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.0.50 (gnu/linux) X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.11 Precedence: list Resent-Date: Sat, 10 Sep 2011 23:30:03 -0400 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.6 (newer, 1) X-Received-From: 140.186.70.43 X-BeenThere: bug-gnu-emacs@gnu.org List-Id: "Bug reports for GNU Emacs, the Swiss army knife of text editors" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane.org@gnu.org Original-Sender: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane.org@gnu.org Xref: news.gmane.org gmane.emacs.bugs:50832 Archived-At: >> In semantic/bovine/c-by.el there=E2=80=99s the following description: >> ("void" summary "Built in typeless type: void") >> Cute, but inaccurate: void is a type alright. I suggest changing >> =E2=80=9Ctypeless type=E2=80=9D to =E2=80=9Cempty type=E2=80=9D. > I don't quite think that "empty type" is more meaningful than "typeless > type". At least to me, "typeless type" makes more sense, even if it is > somewhat humorous. I beg to disagree: to a large extent, a type can be thought of as a set of values. So a type can be empty (meaning that there is no value of that type). But a "typeless type" is rather meaningless (in type theory, types have themselves a type, so for example "1" has type "Int" and "Int" has type "Type", but then a type can't be "typeless" since the "definition" of a type is then basically "has type Type"). Stefan PS: Of course, in C the "void" type is more like the "unit" type than like the empty type, i.e. a type with a single value which hence doesn't carry any information. E.g. a function that returns a type void can return, tho its return value carries no information ("it returns nothing") whereas a function that returns the empty type is a function that will never return (since there is no value in the empty type, the function can never return a value of the right type).