From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Jean Louis Newsgroups: gmane.emacs.help Subject: Re: How can function know its own name? Date: Sun, 26 Jun 2022 11:08:26 +0300 Message-ID: References: Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="2171"; mail-complaints-to="usenet@ciao.gmane.io" User-Agent: Mutt/+ () (2022-05-21) Cc: Help GNU Emacs To: tomas@tuxteam.de Original-X-From: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane-mx.org@gnu.org Sun Jun 26 12:04:57 2022 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 1o5P8S-0000LP-Ag for geh-help-gnu-emacs@m.gmane-mx.org; Sun, 26 Jun 2022 12:04:56 +0200 Original-Received: from localhost ([::1]:32862 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1o5P8Q-0005xt-VJ for geh-help-gnu-emacs@m.gmane-mx.org; Sun, 26 Jun 2022 06:04:54 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:54920) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1o5P7i-0005xj-W8 for help-gnu-emacs@gnu.org; Sun, 26 Jun 2022 06:04:11 -0400 Original-Received: from stw1.rcdrun.com ([217.170.207.13]:39581) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1o5P7f-0004Qt-Cb for help-gnu-emacs@gnu.org; Sun, 26 Jun 2022 06:04:10 -0400 Original-Received: from localhost ([::ffff:197.239.5.50]) (AUTH: PLAIN admin, TLS: TLS1.3,256bits,ECDHE_RSA_AES_256_GCM_SHA384) by stw1.rcdrun.com with ESMTPSA id 0000000000087C50.0000000062B82EF2.00007B1A; Sun, 26 Jun 2022 03:03:30 -0700 Mail-Followup-To: tomas@tuxteam.de, Help GNU Emacs Content-Disposition: inline In-Reply-To: Received-SPF: pass client-ip=217.170.207.13; envelope-from=bugs@gnu.support; helo=stw1.rcdrun.com X-Spam_score_int: -17 X-Spam_score: -1.8 X-Spam_bar: - X-Spam_report: (-1.8 / 5.0 requ) BAYES_00=-1.9, RCVD_IN_SBL=0.141, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=no autolearn_force=no X-Spam_action: no action X-BeenThere: help-gnu-emacs@gnu.org X-Mailman-Version: 2.1.29 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:138102 Archived-At: * tomas@tuxteam.de [2022-06-26 08:46]: > On Sat, Jun 25, 2022 at 11:21:20PM +0300, Jean Louis wrote: > > > > I would like to invoke logging for specific functions automatically, > > without specifying what to log, and my function should know which > > function invoked it. > > This is not completely trivial. In Lisp, a function has no name. > It is a first-class object which can be bound to (the function > slot) of a symbol (or to that of two, three... symbols). > > It's like the value 42. Many variables can be bound to that. Or > none. > > What name has (lambda (x) (if (= (mod x 2) 1) (+ (* 3 x) 1) (/ x 2)))? > > None (yet?). > > Try this: > > (setf (symbol-function 'foo) (lambda (x) (+ x 1))) > > Now: > > (foo 13) > > => 14 > > So that function that adds one to its argument is now arguably > called foo. But: > > (setf (symbol-function 'bar) (symbol-function 'foo)) > > Then: > > (bar 14) > > => 15 > > ...it can be called bar at the same time. Well, I can be called > two names too, can't I? > > See 13.3 "Naming a function" and 9.1 "Symbol Components" in our > beloved Emacs Lisp manual for all the gory details. > > Now to the interesting question: how do debuggers pull it off? OK. Maybe one way to give function a capacity to find out its name, the name of the called function from inside of itself could be to call it in a wrapper which sets global variable to be symbol of the function. (defvar rcd-called-function) (defun rcd-call-function (function &rest args) (setq rcd-called-function function) (apply function args) (setq rcd-called-function nil)) (defun my-fun () (message "My function name is: %s" rcd-called-function)) (rcd-call-function 'my-fun) ⇒ nil -- Jean Take action in Free Software Foundation campaigns: https://www.fsf.org/campaigns In support of Richard M. Stallman https://stallmansupport.org/