From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!.POSTED!not-for-mail From: Andy Moreton Newsgroups: gmane.emacs.devel Subject: Re: Replace trivial pcase occurrences in the Emacs sources Date: Fri, 26 Oct 2018 00:53:47 +0100 Message-ID: <86mur137n8.fsf@gmail.com> References: <20151216202605.GA3752@acm.fritz.box> <56892334.4000106@yandex.ru> <8760zakb7q.fsf@fencepost.gnu.org> <56892BDA.6060103@dancol.org> <871t9yk98g.fsf@fencepost.gnu.org> <568936F0.3060505@yandex.ru> <87wprqitj5.fsf@fencepost.gnu.org> <56893C8C.3060200@yandex.ru> <87oad2irtd.fsf@fencepost.gnu.org> <5689456A.1010601@yandex.ru> <87egdy8tyz.fsf@fencepost.gnu.org> <56895FDE.4060406@yandex.ru> <8760za8r4a.fsf@fencepost.gnu.org> <87h9iunkcg.fsf@web.de> <87h8hc4xw2.fsf_-_@web.de> <83tvlcsnee.fsf@gnu.org> NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: text/plain X-Trace: blaine.gmane.org 1540511526 3931 195.159.176.226 (25 Oct 2018 23:52:06 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Thu, 25 Oct 2018 23:52:06 +0000 (UTC) User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/27.0.50 (windows-nt) To: emacs-devel@gnu.org Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Fri Oct 26 01:52:02 2018 Return-path: Envelope-to: ged-emacs-devel@m.gmane.org Original-Received: from lists.gnu.org ([208.118.235.17]) by blaine.gmane.org with esmtp (Exim 4.84_2) (envelope-from ) id 1gFpQ1-0000sn-6b for ged-emacs-devel@m.gmane.org; Fri, 26 Oct 2018 01:52:01 +0200 Original-Received: from localhost ([::1]:57368 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gFpS7-0007Mm-Mh for ged-emacs-devel@m.gmane.org; Thu, 25 Oct 2018 19:54:11 -0400 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:35171) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gFpRy-0007Mf-Jm for emacs-devel@gnu.org; Thu, 25 Oct 2018 19:54:03 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1gFpRv-0001u1-EP for emacs-devel@gnu.org; Thu, 25 Oct 2018 19:54:02 -0400 Original-Received: from [195.159.176.226] (port=46692 helo=blaine.gmane.org) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1gFpRv-0001t5-66 for emacs-devel@gnu.org; Thu, 25 Oct 2018 19:53:59 -0400 Original-Received: from list by blaine.gmane.org with local (Exim 4.84_2) (envelope-from ) id 1gFpPl-0000ak-Oa for emacs-devel@gnu.org; Fri, 26 Oct 2018 01:51:45 +0200 X-Injected-Via-Gmane: http://gmane.org/ Original-Lines: 20 Original-X-Complaints-To: usenet@blaine.gmane.org Cancel-Lock: sha1:iH6AsH08zCf/hMFBdXIZuv0n7z0= 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:230673 Archived-At: On Thu 25 Oct 2018, Stefan Monnier wrote: >> This raises the question: can we develop a clearer alternative spec >> for a new constuct? Would people like to try out various alternatives? > > Indeed, this can be done without having to re-implement the underlying > machinery since you can easily use a macro-layer on top of pcase > (either via normal defmacro or via pcase-defmacro, or both). ...which does not help existing users, who are still dealing with inadequate documentation of the pcase family of macros, and with the baffling syntax. pcase-lambda, pcase-let, pcase-let*, and pcase-dolist still have no meaningful documentation, and are not even mentioned in the manual. Pattern matching is a useful facility, but pcase is woefully hard to use correctly, as the existing (mis-)usage shows. Something that is significantly easier to read and comprehend is needed. AndyM