From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.ciao.gmane.io!not-for-mail From: Stefan Monnier Newsgroups: gmane.emacs.devel Subject: Re: make-vector documentation is wrong Date: Thu, 14 May 2020 23:41:52 -0400 Message-ID: References: <0430a770-2bb8-2d46-9b28-420c8a6e0a24@dancol.org> <5bcc3508-9d65-c5b4-255e-898f8e1dc3c1@cs.ucla.edu> Mime-Version: 1.0 Content-Type: text/plain Injection-Info: ciao.gmane.io; posting-host="ciao.gmane.io:159.69.161.202"; logging-data="33722"; mail-complaints-to="usenet@ciao.gmane.io" User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/28.0.50 (gnu/linux) Cc: Daniel Colascione , Emacs developers To: Paul Eggert Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Fri May 15 05:42:34 2020 Return-path: Envelope-to: ged-emacs-devel@m.gmane-mx.org Original-Received: from lists.gnu.org ([209.51.188.17]) by ciao.gmane.io with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1jZRF3-0008eR-1u for ged-emacs-devel@m.gmane-mx.org; Fri, 15 May 2020 05:42:33 +0200 Original-Received: from localhost ([::1]:57580 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jZRF2-0007sL-4B for ged-emacs-devel@m.gmane-mx.org; Thu, 14 May 2020 23:42:32 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:54710) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jZREZ-0007S6-O9 for emacs-devel@gnu.org; Thu, 14 May 2020 23:42:03 -0400 Original-Received: from mailscanner.iro.umontreal.ca ([132.204.25.50]:51168) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jZREX-0007An-VX for emacs-devel@gnu.org; Thu, 14 May 2020 23:42:02 -0400 Original-Received: from pmg2.iro.umontreal.ca (localhost.localdomain [127.0.0.1]) by pmg2.iro.umontreal.ca (Proxmox) with ESMTP id 4FD0F807F5; Thu, 14 May 2020 23:42:00 -0400 (EDT) Original-Received: from mail01.iro.umontreal.ca (unknown [172.31.2.1]) by pmg2.iro.umontreal.ca (Proxmox) with ESMTP id 79277806A2; Thu, 14 May 2020 23:41:54 -0400 (EDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=iro.umontreal.ca; s=mail; t=1589514114; bh=jHy4/k6sEl/lkj/J3CIW+oCNiLiZ13V+iqAOqvUJN5I=; h=From:To:Cc:Subject:References:Date:In-Reply-To:From; b=c/j7zyoUSa2h0xraiOigP+PCsHKICO0bBDhkBOkvLQVXhGgzsraM8/TCP1CiTSD9p dUNolP/2DpN0U47ZiuADXYR9bp4naVWbhNUZFMRorSlUHb4aC8A/asLOL8y794qt8C ro28bSC4x3BhfgLRpqJO3qmvt6BBBKd4tFG6+AgT7LzqWVnvf8VgK4daiKVBIE+slQ FFuP2n9KRougqq1ZRqfitkCrgd9V9sC/DCHf7Ydz78FHC029gYlU5ovcBdh9Q6DK21 Sxrxr80D730DLpIlMhevnddrxRlGegmvB81e1LE/L9Vc8jr3mmUz5C6Hb2gvy2F3PU 89qOvIs1/Gk9g== Original-Received: from alfajor (unknown [216.154.3.202]) by mail01.iro.umontreal.ca (Postfix) with ESMTPSA id 326931202BA; Thu, 14 May 2020 23:41:54 -0400 (EDT) In-Reply-To: <5bcc3508-9d65-c5b4-255e-898f8e1dc3c1@cs.ucla.edu> (Paul Eggert's message of "Thu, 14 May 2020 19:46:09 -0700") Received-SPF: pass client-ip=132.204.25.50; envelope-from=monnier@iro.umontreal.ca; helo=mailscanner.iro.umontreal.ca X-detected-operating-system: by eggs.gnu.org: First seen = 2020/05/14 23:42:00 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] X-Spam_score_int: -42 X-Spam_score: -4.3 X-Spam_bar: ---- X-Spam_report: (-4.3 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, RCVD_IN_DNSWL_MED=-2.3, SPF_PASS=-0.001, URIBL_BLOCKED=0.001 autolearn=_AUTOLEARN X-Spam_action: no action X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: "Emacs development discussions." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Original-Sender: "Emacs-devel" Xref: news.gmane.io gmane.emacs.devel:250333 Archived-At: > (make-string 0 0), (make-list 0 0), (vector), and (list) all have the property > that (make-vector 0 0) does - that is, each call returns the same empty object > each time. I imagine that make-vector was implemented to be consistent with the > other functions - at least, this behavior appears to be a conscious decision > rather than accidental. So it may make sense to change these functions' > documentation instead of their implementation's longstanding behavior. Actually, IIRC, for vectors it wasn't done "to make things consistent" but because it simplified the memory management (IIRC the malloc-like level needed its smallest object to be bigger than a 0-length vector, so instead of adding an ad-hoc exception for 0-length vectors to artificially use up more space, we decided to return a constant because it was both simpler and more efficient). I can't see any strong argument either for making sure (vector) returns a fresh object nor for enforcing that it always returns the same object, so I'd favor a documentation that says both things are valid (i.e. Elisp code shouldn't rely on either behavior). Stefan