From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!.POSTED.blaine.gmane.org!not-for-mail From: Andy Moreton Newsgroups: gmane.emacs.devel Subject: Re: Why is FUNC in cl-callf not allowed to be an expression? Date: Tue, 21 May 2019 08:26:03 +0100 Message-ID: <8636l846b8.fsf@gmail.com> References: <874l631ek1.fsf@web.de> <87pnoqtuhm.fsf@web.de> <87r2961gox.fsf@web.de> <87mujohasa.fsf@web.de> <87a7fn3c6c.fsf@web.de> <875zqabh3t.fsf@web.de> <87zhnma11c.fsf@web.de> <871s0y3weo.fsf@web.de> <87tvdshew9.fsf@web.de> <87k1ek673s.fsf@web.de> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Injection-Info: blaine.gmane.org; posting-host="blaine.gmane.org:195.159.176.226"; logging-data="29894"; mail-complaints-to="usenet@blaine.gmane.org" User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/26.2.50 (windows-nt) To: emacs-devel@gnu.org Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Tue May 21 09:27:02 2019 Return-path: Envelope-to: ged-emacs-devel@m.gmane.org Original-Received: from lists.gnu.org ([209.51.188.17]) by blaine.gmane.org with esmtps (TLS1.0:RSA_AES_256_CBC_SHA1:256) (Exim 4.89) (envelope-from ) id 1hSzAq-0007au-IW for ged-emacs-devel@m.gmane.org; Tue, 21 May 2019 09:27:00 +0200 Original-Received: from localhost ([127.0.0.1]:48169 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hSzAp-0003ux-3F for ged-emacs-devel@m.gmane.org; Tue, 21 May 2019 03:26:59 -0400 Original-Received: from eggs.gnu.org ([209.51.188.92]:33847) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hSzAA-0003tV-4V for emacs-devel@gnu.org; Tue, 21 May 2019 03:26:18 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hSzA9-0006OM-9W for emacs-devel@gnu.org; Tue, 21 May 2019 03:26:18 -0400 Original-Received: from [195.159.176.226] (port=43354 helo=blaine.gmane.org) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hSzA9-0006NB-25 for emacs-devel@gnu.org; Tue, 21 May 2019 03:26:17 -0400 Original-Received: from list by blaine.gmane.org with local (Exim 4.89) (envelope-from ) id 1hSzA5-0006l6-1t for emacs-devel@gnu.org; Tue, 21 May 2019 09:26:13 +0200 X-Injected-Via-Gmane: http://gmane.org/ Cancel-Lock: sha1:wyLgm30m/EgiX0WoJ90hyX8Q6wc= 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:236839 Archived-At: On Mon 20 May 2019, Stefan Monnier wrote: >> Sorry that I haven't been clear: I want EXPR to eval to the function to >> be applied, not to the expression to set to. Like in >> >> (cl-callf (with (if flag #'1+ #'1-)) my-number) > > Note that the gv-modify macro we discussed does not allow that either: > it doesn't funcall the result of an EXPR. > > So, what you want can be written > > (cl-callf (lambda (x) (if flag (1+ x) (1- x))) my-number) > or > (cl-callf (lambda (x) (funcall (if flag #'1+ #'1-) x)) my-number) The documentation for `cl-callf' says: Set PLACE to (FUNC PLACE ARGS...). FUNC should be an unquoted function name. PLACE may be a symbol, or any generalized variable allowed by ‘setf’. Please update this (and `cl-callf2') to show that FUNC can be a lambda. Thanks, AndyM