From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Drew Adams Newsgroups: gmane.emacs.devel Subject: RE: [External] : Re: Conditional binding and testing of `lexical-binding' Date: Sun, 2 Jan 2022 23:01:25 +0000 Message-ID: References: <874k6mjomk.fsf@yahoo.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="25216"; mail-complaints-to="usenet@ciao.gmane.io" Cc: "emacs-devel@gnu.org" To: Stefan Monnier , Po Lu Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Mon Jan 03 00:04:53 2022 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 1n49uG-0006L3-7g for ged-emacs-devel@m.gmane-mx.org; Mon, 03 Jan 2022 00:04:52 +0100 Original-Received: from localhost ([::1]:52774 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1n49uF-0001vo-2z for ged-emacs-devel@m.gmane-mx.org; 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envelope-from=drew.adams@oracle.com; helo=mx0a-00069f02.pphosted.com X-Spam_score_int: -8 X-Spam_score: -0.9 X-Spam_bar: / X-Spam_report: (-0.9 / 5.0 requ) DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=unavailable 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" Xref: news.gmane.io gmane.emacs.devel:283980 Archived-At: > > OTOH, I don't think there's much to be gained by using lexical binding > > at all in code that's supposed to be compatible with versions of Emacs > > without lexical binding. >=20 > You get better byte-compiler warnings, and the native code generated > from it is of higher quality, so it's likely to be marginally faster in > such a build. Yes, I suggested that (but I said byte-compile, not native-compile). But of course that's only when you compile with Emacs 24+. It's the difference between Emacs knowing that the value is a function versus it only being able to know for sure that it's a list with a `lambda' car. When a compiler knows that it's a function it can sometimes take advantage of that - beyond just providing better warnings. > Nothing ground breaking, admittedly. Yes, I said that too. Besides immediate minor advantages, it presents the advantage of being the code to use if/when the library later drops compatibility with Emacs 23 and prior - that's the part to keep, then.