From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Eric Abrahamsen Newsgroups: gmane.emacs.devel Subject: Re: Compiler macro for apply-partially Date: Wed, 25 Aug 2021 10:45:15 -0700 Message-ID: <87k0k9beqc.fsf@ericabrahamsen.net> References: <87a6l74abo.fsf@alphapapa.net> Mime-Version: 1.0 Content-Type: text/plain Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="37683"; mail-complaints-to="usenet@ciao.gmane.io" User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/28.0.50 (gnu/linux) Cc: Adam Porter , emacs-devel@gnu.org To: Stefan Monnier Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Wed Aug 25 19:46:20 2021 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 1mIwyh-0009ZL-Ps for ged-emacs-devel@m.gmane-mx.org; Wed, 25 Aug 2021 19:46:19 +0200 Original-Received: from localhost ([::1]:47778 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1mIwyg-0001uu-9H for ged-emacs-devel@m.gmane-mx.org; Wed, 25 Aug 2021 13:46:18 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:54352) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mIwxs-0001Bj-3M for emacs-devel@gnu.org; Wed, 25 Aug 2021 13:45:28 -0400 Original-Received: from mail.ericabrahamsen.net ([52.70.2.18]:51418) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mIwxp-0005Q1-K3 for emacs-devel@gnu.org; Wed, 25 Aug 2021 13:45:27 -0400 Original-Received: from localhost (c-73-109-4-106.hsd1.wa.comcast.net [73.109.4.106]) (Authenticated sender: eric@ericabrahamsen.net) by mail.ericabrahamsen.net (Postfix) with ESMTPSA id CFDC6FA827; Wed, 25 Aug 2021 17:45:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ericabrahamsen.net; s=mail; t=1629913517; bh=EHBinjr83xGdoDENRIcAieA5cYwf184HzZeQ5dTgSeI=; h=From:To:Cc:Subject:References:Date:In-Reply-To:From; b=fGkWaVcyqD4FG16msytCN2zLvpmlTQy0LZ4Xg21E4UQnU31W1p91d23Ti//mlrcDq IPTw4LnRdd9PUwRh1FhuG9v/6scq8CqbSxnVrHvOTv4Mea7KRaWZahkI+9zLIirbw2 1lSPBM2cb5C9mRj90V8f80WHl6Y/U7u++PgsDm4g= In-Reply-To: (Stefan Monnier's message of "Tue, 24 Aug 2021 18:32:55 -0400") Received-SPF: pass client-ip=52.70.2.18; envelope-from=eric@ericabrahamsen.net; helo=mail.ericabrahamsen.net X-Spam_score_int: -43 X-Spam_score: -4.4 X-Spam_bar: ---- X-Spam_report: (-4.4 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_MED=-2.3, SPF_HELO_NONE=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: 2.1.23 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:272986 Archived-At: Stefan Monnier writes: >> (defun apply-partially* (fun &rest args) >> "Return a function that is a partial application of FUN to ARGS. >> ARGS is a list of the first N arguments to pass to FUN. The >> result is a new function which does the same as FUN, except that >> the first N arguments are fixed at the values with which this >> function was called." >> (declare (compiler-macro (lambda (exp) >> `(lambda (&rest args2) >> (apply ,fun ,@args args2))))) >> (lambda (&rest args2) >> (apply fun (append args args2)))) > > Looks OK to me. > > FWIW, I never added such a compiler macro for the following reason: it's > almost always preferable to use an explicit `lambda` where you can > specify how many args are expected and hence avoid the `&rest` and the > `apply`, leading to significantly more efficient code. For us slower kids, this explicit approach might look like: (cl-flet ((curried (arg3) (function-to-apply-partially arg1 arg2 arg3))) (curried "arg3")) Either that or just plain `let' a lambda, and then `funcall' it?