From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Michael Heerdegen Newsgroups: gmane.emacs.help Subject: Re: How to save custom variable programmatically? Date: Tue, 10 Nov 2020 22:15:58 +0100 Message-ID: <87h7pwgbg1.fsf@web.de> References: <87blg5e9re.fsf@web.de> <87o8k5b7oq.fsf@web.de> Mime-Version: 1.0 Content-Type: text/plain Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="5382"; mail-complaints-to="usenet@ciao.gmane.io" User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/28.0.50 (gnu/linux) To: help-gnu-emacs@gnu.org Cancel-Lock: sha1:5z/OebHf0U/6WCrnNdrBj7iJ7dU= Original-X-From: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane-mx.org@gnu.org Tue Nov 10 22:17:21 2020 Return-path: Envelope-to: geh-help-gnu-emacs@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 1kcb0z-0001Gv-Cw for geh-help-gnu-emacs@m.gmane-mx.org; Tue, 10 Nov 2020 22:17:21 +0100 Original-Received: from localhost ([::1]:39616 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kcb0y-0005uP-CR for geh-help-gnu-emacs@m.gmane-mx.org; Tue, 10 Nov 2020 16:17:20 -0500 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:52012) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kcazq-0005t5-8b for help-gnu-emacs@gnu.org; Tue, 10 Nov 2020 16:16:11 -0500 Original-Received: from static.214.254.202.116.clients.your-server.de ([116.202.254.214]:40574 helo=ciao.gmane.io) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kcazn-00063T-RR for help-gnu-emacs@gnu.org; Tue, 10 Nov 2020 16:16:09 -0500 Original-Received: from list by ciao.gmane.io with local (Exim 4.92) (envelope-from ) id 1kcazk-000AS2-5h for help-gnu-emacs@gnu.org; Tue, 10 Nov 2020 22:16:04 +0100 X-Injected-Via-Gmane: http://gmane.org/ Received-SPF: pass client-ip=116.202.254.214; envelope-from=geh-help-gnu-emacs@m.gmane-mx.org; helo=ciao.gmane.io X-detected-operating-system: by eggs.gnu.org: First seen = 2020/11/10 09:16:09 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -13 X-Spam_score: -1.4 X-Spam_bar: - X-Spam_report: (-1.4 / 5.0 requ) BAYES_00=-1.9, FREEMAIL_FORGED_FROMDOMAIN=0.25, FREEMAIL_FROM=0.001, HEADER_FROM_DIFFERENT_DOMAINS=0.25, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=no autolearn_force=no X-Spam_action: no action X-BeenThere: help-gnu-emacs@gnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Users list for the GNU Emacs text editor List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane-mx.org@gnu.org Original-Sender: "help-gnu-emacs" Xref: news.gmane.io gmane.emacs.help:125213 Archived-At: Jean Louis writes: > Thank you. If you have ready simplest example it may be useful for > review. Simplest? Ok, that might be possible. Let's make a wrapper holding a single value that is savable: #+begin_src emacs-lisp (defclass my-persistent (eieio-persistent) ((data :initarg :data))) (defun my-save-in-location (thing file) (let ((obj (my-persistent :data thing))) (setf (oref obj file) file) (eieio-persistent-save obj))) ;; save a value to a file: (my-save-in-location (list 'x [] "Hello") (expand-file-name "~/test")) ;; get it back: (oref (eieio-persistent-read (expand-file-name "~/test") 'my-persistent) :data) ;; ==> (x [] "Hello") #+end_src This is not only a nice abstraction. eieio-persistent has some (programmable) knowledge about how to print and "restore" objects where a normal print+read cycle would not work. Michael.