From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Ulrich Mueller Newsgroups: gmane.emacs.devel Subject: Re: Why shouldn't we have a #if .... #else .... #endif construct in Emacs Lisp? Date: Tue, 05 Sep 2023 10:14:20 +0200 Message-ID: References: Mime-Version: 1.0 Content-Type: text/plain Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="35080"; mail-complaints-to="usenet@ciao.gmane.io" User-Agent: Gnus/5.13 (Gnus v5.13) Cc: emacs-devel@gnu.org To: Alan Mackenzie Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Tue Sep 05 10:15:23 2023 Return-path: Envelope-to: ged-emacs-devel@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 1qdRDW-0008vW-MC for ged-emacs-devel@m.gmane-mx.org; Tue, 05 Sep 2023 10:15:22 +0200 Original-Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1qdRCh-0007NN-Np; Tue, 05 Sep 2023 04:14:32 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1qdRCh-0007NF-1U for emacs-devel@gnu.org; Tue, 05 Sep 2023 04:14:31 -0400 Original-Received: from woodpecker.gentoo.org ([140.211.166.183] helo=smtp.gentoo.org) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_CHACHA20_POLY1305:256) (Exim 4.90_1) (envelope-from ) id 1qdRCe-0004re-G4 for emacs-devel@gnu.org; Tue, 05 Sep 2023 04:14:30 -0400 In-Reply-To: (Alan Mackenzie's message of "Mon, 28 Aug 2023 21:46:46 +0000") Received-SPF: pass client-ip=140.211.166.183; envelope-from=ulm@gentoo.org; helo=smtp.gentoo.org X-Spam_score_int: -41 X-Spam_score: -4.2 X-Spam_bar: ---- X-Spam_report: (-4.2 / 5.0 requ) BAYES_00=-1.9, RCVD_IN_DNSWL_MED=-2.3, RCVD_IN_MSPIKE_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.29 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-mx.org@gnu.org Original-Sender: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Xref: news.gmane.io gmane.emacs.devel:310117 Archived-At: >>>>> On Mon, 28 Aug 2023, Alan Mackenzie wrote: >> Sorry, I should have been clearer. The full construct would look like >> this: >> (when (eval-when-compile (< emacs-major-version 24)) >> (defadvice .....)) > Ah! So the eval-when-compile gets compiled to a constant nil or t, and > the byte compiler optimises the test of this out, either compiling or > not compiling the (defadvice .....). Thanks! I hadn't been aware of > that little detail. >> So only the test would be evaluated at compile time, the defadvice >> itself would be compiled normally (or not, if the test fails). I've just tested with current master. Byte-compiling this: (static-if (> emacs-major-version 24) (message "new emacs") (message "old emacs")) and this: (if (eval-when-compile (> emacs-major-version 24)) (message "new emacs") (message "old emacs")) results in identical byte code. > However, when evaluating the containing defun/defmacro rather than byte > compiling it, the irritating warning message will appear with the e-w-c > strategem, but not with hash-if. ;-) Sorry, I cannot reproduce this problem. Could you give an example?