From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!.POSTED.blaine.gmane.org!not-for-mail From: Michael Heerdegen Newsgroups: gmane.emacs.devel Subject: Re: Why is FUNC in cl-callf not allowed to be an expression? Date: Wed, 15 May 2019 18:38:51 +0200 Message-ID: <87a7fn3c6c.fsf@web.de> References: <874l631ek1.fsf@web.de> <87pnoqtuhm.fsf@web.de> <87r2961gox.fsf@web.de> <87mujohasa.fsf@web.de> Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: quoted-printable Injection-Info: blaine.gmane.org; posting-host="blaine.gmane.org:195.159.176.226"; logging-data="152338"; mail-complaints-to="usenet@blaine.gmane.org" User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/27.0.50 (gnu/linux) Cc: emacs-devel@gnu.org To: Stefan Monnier Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Wed May 15 18:39:44 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 1hQwwR-000dXx-I6 for ged-emacs-devel@m.gmane.org; Wed, 15 May 2019 18:39:43 +0200 Original-Received: from localhost ([127.0.0.1]:39667 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hQwwQ-0001br-Az for ged-emacs-devel@m.gmane.org; Wed, 15 May 2019 12:39:42 -0400 Original-Received: from eggs.gnu.org ([209.51.188.92]:32821) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hQwvn-0001bh-Ja for emacs-devel@gnu.org; Wed, 15 May 2019 12:39:04 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hQwvm-0004ol-Hq for emacs-devel@gnu.org; Wed, 15 May 2019 12:39:03 -0400 Original-Received: from mout.web.de ([217.72.192.78]:35877) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1hQwvm-0004nG-7Z for emacs-devel@gnu.org; Wed, 15 May 2019 12:39:02 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=web.de; s=dbaedf251592; t=1557938334; bh=zWC6Txy0ybldOG//hQnLukPRC3Qh6fdlHnbDz4ijmqA=; h=X-UI-Sender-Class:From:To:Cc:Subject:References:Date:In-Reply-To; b=fgMvMtIZFjcyx8ma4NnEPBFHqVpWB4QsGwyy3xm+YouZj1qYAd7jtEEcpNs92If13 Gm0+fea5I8d+CsLI9rOOkimZXFF2B9WYH3uUkfyGslIXnGfry/3FqXZf0omLe7tX7g 0wd47wZH0pvJoWanxDjAsLNKPyLpkIMRHWvnCxOw= X-UI-Sender-Class: c548c8c5-30a9-4db5-a2e7-cb6cb037b8f9 Original-Received: from drachen.dragon ([188.110.143.34]) by smtp.web.de (mrweb101 [213.165.67.124]) with ESMTPSA (Nemesis) id 0MD87M-1hS77Z3FCm-00GVUq; Wed, 15 May 2019 18:38:53 +0200 In-Reply-To: (Stefan Monnier's message of "Tue, 14 May 2019 22:02:06 -0400") X-Provags-ID: V03:K1:IP/IVy4VIwzWFuBLR4hTM2mZGRNUU00Ot6tbm8XjlR/6brY47Ag DX8+Y0VYAuhK3Sq4DYHUc2DhpYEVSPcZFWo5Jy0O6A6BYbBY/h/r2l4klv81CSo+Ww0tIrY 9S6g4WLTa7fXMrdUtW62pg2ibW6Ew40CzjfT5ztoL33Td18KGqo4V0kgrVimXInJu5iuM0i 2SRSatzHqMoi1szKNGjuQ== X-UI-Out-Filterresults: notjunk:1;V03:K0:J5JPjRVlrVc=:g52yi/hr2VJzhMKl8bXOM7 u/l5iOVmcIqaay0omPkSh6gpHfPBoVyeaEsVxzPCeS9MBQTHqJzXE/mnuBDvZfT7VMd5siFoy B3dyirHvJYmqyusr+F3bqlDUnOGjGqEWOXc1cetBTcwWKUOJnU6kK9sa9R8Av9kCvvL8xuBqD 9sf/nUeDn5UfATaY91lan89JRvGZubjg0yqT64OU7uax2Zb71xbR/7TsbFRVsVlkOQb3Igql9 ILdDkVGQc8yHmEX2VQoszWRcE3ClFexVBkEDWhdlmqSqapY7vyDaInZSblsi7QOMrJ5Wjn7tF Q5sN8LQi3ar+L+iGrhLUyfR82cTzTHMEhHZsgfuWl7qH7Vv5fy7RIpeSB0eVF6eyKFmSJDeqj C1PC8DKbA/tuwTPXAoKy/Y9OjTm1soOX3Yw99ECN7OaeJt8vA0Nm64tEbO7z0qtPK3zjvQLR+ 0l4gPstOJ++GV3SoVB03geXNNQaLqcFnwxfui0h5ZbQDyu65To4lgJfqurx5tPaeeODQP8RGp qLq77Vr8klzBTYAnCSjIrtSZ20dym9M5fObpPTaTVdnSlDggPkpPEQtKlBnQmUBx6g9aymq3n IaJ3m1Z0CYOzjm6vzzo8dUMuKCkYcnuHPOT86eO6/wmej2g2ZFA1YJUd/1ih7dxraYCItLf0w 5G7ERzFGCBIKv+xwPvAv2pVWRVDlZhvy7c5iwekg/kf9bmsAWb+1WENdL+klaekLEsDrJpG67 5hyNCCf1yzDsW/Sz+qD9SUrGvN8C/eKGgDEQ3iLkj/ZjiQ98N0dT34fG+F9tX/7CTL0HRE2I X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 217.72.192.78 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:236544 Archived-At: Stefan Monnier writes: > > (defmacro gv-with-place (place f) > > (declare (indent 1)) > > (gv-letplace (getter setter) place > > (let ((v (make-symbol "v"))) > > `(funcall ,f ,getter (lambda (,v) ,(funcall setter v)))))) > > We could at least avoid the overall `funcall`: > > (defmacro gv-with-place (val setfun place &rest body) > (declare (indent 3)) > (gv-letplace (getter setter) place > `(let ((,val ,getter) > (,setfun (lambda (v) ,(funcall setter 'v)))) > ,@body))) Yes, or maybe even (defmacro gv-with-place (val-sym setfun-sym place &rest body) (declare (indent 3)) (gv-letplace (getter setter) place (let ((v (make-symbol "v"))) `(cl-flet ((,setfun-sym (lambda (,v) ,(funcall setter v)))) (let ((,val-sym ,getter)) ,@body))))) Example: (let ((l '(2 3 4))) (gv-with-place p set (cdr l) (unless (memq 1 p) (set (cons 1 p)))) l) =3D=3D> (2 1 3 4) > Along the same lines maybe we could provide a (gv-ref VAL SETFUN) > pcase-macro, so you could do > > (pcase-let (((gv-ref val setter) (gv-ref PLACE))) > (unless (member X val) (funcall setter (cons X val)))) > > Even better would be if we could do > > (pcase-let (((gv-ref p) (gv-ref PLACE))) > (unless (member X p) (setf p (cons X p)))) > > but it seems this would require non-trivial changes to pcase (since > basically `p` should not be bound there with a `let` but with > a `cl-symbol-macrolet`). I tried to implement more or less that as a normal macro: (defun gv-ad-hoc-place (val _setter) (declare (compiler-macro (lambda (_) val)) (gv-expander funcall)) val) (defmacro gv-do-place (place-sym place &rest body) (declare (indent 2)) (gv-letplace (getter setter) place `(let ((val ,getter)) (cl-symbol-macrolet ((,place-sym (gv-ad-hoc-place val ,setter))) ,@body)))) Example: (let ((l '(2 3 4))) (gv-do-place p (cdr l) (unless (memq 1 p) (setf p (cons 1 p)))) l) =3D=3D> (2 1 3 4) Note that `gv-synthetic-place' can't be used here because in setf it would just expand to (setq val ...) with val being the let-bound symbol in the implementation, instead of something setf'ing the PLACE. > Still, I think the `gv-modify` discussed earlier hits a sweeter spot. Is it still your favorite? Michael.