From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!.POSTED!not-for-mail From: Stefan Monnier Newsgroups: gmane.emacs.devel Subject: Re: `aset` on strings, changing the size in bytes Date: Sat, 08 Sep 2018 18:09:41 -0400 Message-ID: References: <88must56x4.fsf@gnu.org> <83efe4trsa.fsf@gnu.org> <83lg8bsvfm.fsf@gnu.org> <83k1nvso1o.fsf@gnu.org> NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: text/plain X-Trace: blaine.gmane.org 1536444575 9002 195.159.176.226 (8 Sep 2018 22:09:35 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Sat, 8 Sep 2018 22:09:35 +0000 (UTC) User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/27.0.50 (gnu/linux) To: emacs-devel@gnu.org Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Sun Sep 09 00:09:31 2018 Return-path: Envelope-to: ged-emacs-devel@m.gmane.org Original-Received: from lists.gnu.org ([208.118.235.17]) by blaine.gmane.org with esmtp (Exim 4.84_2) (envelope-from ) id 1fylQ3-0002Hg-1M for ged-emacs-devel@m.gmane.org; Sun, 09 Sep 2018 00:09:31 +0200 Original-Received: from localhost ([::1]:45364 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fylS9-0005Cs-5g for ged-emacs-devel@m.gmane.org; Sat, 08 Sep 2018 18:11:41 -0400 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:57216) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fylRy-00059l-Ko for emacs-devel@gnu.org; Sat, 08 Sep 2018 18:11:35 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fylQL-0004OZ-Ll for emacs-devel@gnu.org; Sat, 08 Sep 2018 18:09:54 -0400 Original-Received: from [195.159.176.226] (port=54939 helo=blaine.gmane.org) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1fylQL-0004Mn-E9 for emacs-devel@gnu.org; Sat, 08 Sep 2018 18:09:49 -0400 Original-Received: from list by blaine.gmane.org with local (Exim 4.84_2) (envelope-from ) id 1fylOC-0000Zq-Nm for emacs-devel@gnu.org; Sun, 09 Sep 2018 00:07:36 +0200 X-Injected-Via-Gmane: http://gmane.org/ Original-Lines: 13 Original-X-Complaints-To: usenet@blaine.gmane.org Cancel-Lock: sha1:LuoV0mTFyn88OvSpBAjGN3SLTpw= X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 195.159.176.226 X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.21 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.org@gnu.org Original-Sender: "Emacs-devel" Xref: news.gmane.org gmane.emacs.devel:229521 Archived-At: >> The need for an indirection (a String_Object has to hold a pointer to an >> sdata object rather than being able to keep its payload directly in the >> Lisp_String object (using FLEXIBLE_ARRAY_MEMBER)) > Why is that a problem? It slows down every string access, and increases the heap size of every string (currently they're something like N bytes of payload plus 5 words where 2 of those 5 words are due to the extra indirection). For a feature that's almost never used, I think it's pretty costly. Stefan