From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!.POSTED!not-for-mail From: =?UTF-8?Q?Cl=c3=a9ment_Pit-Claudel?= Newsgroups: gmane.emacs.devel Subject: Re: Changing a cl-defstruct definition in a published package Date: Fri, 13 Jul 2018 14:21:14 -0400 Message-ID: <69d5a564-6620-3691-9fb7-d0798b817f8a@gmail.com> References: <9afc36c6-5759-6ea0-4cd4-9d6eb6b073b5@gmail.com> <87lgaf3uk3.fsf@tcd.ie> NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit X-Trace: blaine.gmane.org 1531505966 27473 195.159.176.226 (13 Jul 2018 18:19:26 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Fri, 13 Jul 2018 18:19:26 +0000 (UTC) User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.8.0 Cc: emacs-devel To: "Basil L. 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[18.26.2.123]) by smtp.gmail.com with ESMTPSA id q13-v6sm22057972qkl.97.2018.07.13.11.21.15 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 13 Jul 2018 11:21:15 -0700 (PDT) In-Reply-To: <87lgaf3uk3.fsf@tcd.ie> Content-Language: en-GB X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. X-Received-From: 2607:f8b0:400d:c0d::22e 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:227360 Archived-At: On 2018-07-13 13:38, Basil L. Contovounesios wrote: > If cl-defstructs boil down to an array in disguise (I don't know because > I've never looked into them), would appending (as opposed to prepending > or inserting) new slots maintain backward compatibility? I don't think so, unfortunately, because of the second issue I mentioned at the end of my email: constructors called on B's side have been compiled down to array initializations, which means that even if the new constructor for my defstruct has a default value set, B will still pass me arrays that are one element too short :/