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: Difficulties with `purecopy' discarding text properties from strings Date: Fri, 19 May 2017 15:22:50 -0400 Message-ID: References: <20170519185508.GA5330@acm.fritz.box> NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: text/plain X-Trace: blaine.gmane.org 1495221795 24584 195.159.176.226 (19 May 2017 19:23:15 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Fri, 19 May 2017 19:23:15 +0000 (UTC) User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/26.0.50 (gnu/linux) To: emacs-devel@gnu.org Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Fri May 19 21:23:12 2017 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 1dBnUV-0006HW-RH for ged-emacs-devel@m.gmane.org; Fri, 19 May 2017 21:23:11 +0200 Original-Received: from localhost ([::1]:60005 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dBnUb-0001yJ-4w for ged-emacs-devel@m.gmane.org; Fri, 19 May 2017 15:23:17 -0400 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:57561) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dBnUT-0001x7-B5 for emacs-devel@gnu.org; Fri, 19 May 2017 15:23:10 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dBnUO-0008HA-BY for emacs-devel@gnu.org; Fri, 19 May 2017 15:23:09 -0400 Original-Received: from [195.159.176.226] (port=54313 helo=blaine.gmane.org) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1dBnUO-0008Fd-4V for emacs-devel@gnu.org; Fri, 19 May 2017 15:23:04 -0400 Original-Received: from list by blaine.gmane.org with local (Exim 4.84_2) (envelope-from ) id 1dBnUD-0005tn-8d for emacs-devel@gnu.org; Fri, 19 May 2017 21:22:53 +0200 X-Injected-Via-Gmane: http://gmane.org/ Original-Lines: 30 Original-X-Complaints-To: usenet@blaine.gmane.org Cancel-Lock: sha1:lEM5EksVcGvxws+PnWQthNV6ZEc= X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] 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:215000 Archived-At: > Presumably there are good reasons for discarding text properties when > purecopying strings. I don't think so. > Or, maybe, there was just no particular reason to amend the workings > of `purecopy' when text properties came into existence. I think that's what happens. But wait a minute: > I naively constructed such a defcustom, with text properties on the > value option strings. How exactly did you do that? Using #("..." ...) or using (propertize "..." ...)? > After some debugging, I discover that defcustom strips those text > properties off the strings. It does this by using `purecopy' on these > strings (in the function `custom-declare-variable'). But AFAICT custom-declare-variable only applies purecopy to its `default` argument which is supposed to be an expression (which evaluates to the intended value) rather than a value. So if you use the (propertize "..." ...) form, the properties should not be stripped. Or am I missing something? Stefan