From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: Michael Heerdegen Newsgroups: gmane.emacs.devel Subject: Re: The poor state of documentation of pcase like things. Date: Sat, 19 Dec 2015 22:09:38 +0100 Message-ID: <87oadmkuwd.fsf@web.de> References: <20151216202605.GA3752@acm.fritz.box> <87mvt859cw.fsf@russet.org.uk> <87poy2tqrc.fsf@web.de> <87mvt6nsxr.fsf@russet.org.uk> NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-Trace: ger.gmane.org 1450559415 11683 80.91.229.3 (19 Dec 2015 21:10:15 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Sat, 19 Dec 2015 21:10:15 +0000 (UTC) Cc: emacs-devel@gnu.org To: phillip.lord@russet.org.uk (Phillip Lord) Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Sat Dec 19 22:10:06 2015 Return-path: Envelope-to: ged-emacs-devel@m.gmane.org Original-Received: from lists.gnu.org ([208.118.235.17]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1aAOlN-0008Rb-GV for ged-emacs-devel@m.gmane.org; Sat, 19 Dec 2015 22:10:01 +0100 Original-Received: from localhost ([::1]:38648 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aAOlM-0000xN-9R for ged-emacs-devel@m.gmane.org; Sat, 19 Dec 2015 16:10:00 -0500 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:46155) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aAOl9-0000xF-59 for emacs-devel@gnu.org; Sat, 19 Dec 2015 16:09:48 -0500 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1aAOl5-00031a-3W for emacs-devel@gnu.org; Sat, 19 Dec 2015 16:09:47 -0500 Original-Received: from mout.web.de ([212.227.17.12]:56145) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aAOl4-00031S-QQ for emacs-devel@gnu.org; Sat, 19 Dec 2015 16:09:43 -0500 Original-Received: from drachen.dragon ([90.186.0.6]) by smtp.web.de (mrweb102) with ESMTPSA (Nemesis) id 0LmLc6-1ak0QR1MkE-00ZvaL; Sat, 19 Dec 2015 22:09:41 +0100 In-Reply-To: <87mvt6nsxr.fsf@russet.org.uk> (Phillip Lord's message of "Sat, 19 Dec 2015 19:23:44 +0000") User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/25.0.50 (gnu/linux) X-Provags-ID: V03:K0:nhMawMTzcdxyCz3BvwlAUlDPn0Oe9fmC3z/Z2B7nwHEZdypKz8v VekR8GbJDTt46KwrW4alBzOhxEcWf4cjO8VOgpWORU7ZnpyAfOYPKS+nWQT9lUjEpbeTFrs gpgmYcFg52i6E7PPAzl8DCCnbMB9rtJ7PAFLGfGnk4YwvBmT2VpST9lkjB9iDScMzSe2f9O PjK5sqRTaJ/KflpUlcb/w== X-UI-Out-Filterresults: notjunk:1;V01:K0:A6nTlX/vm8E=:oSkm0dje9a+TOjk0EDX39W lIIjbkxzbtUqAdaFpqJgygaCf58lYFweId8c+TzstZIyc6yuge24fGqUEpH0l6LMaLyyL82t6 8exDlS3fg+69QXfUJPDlcEaiFH3bSCaNHFy2/rFLisreNw0bcmdwVIexwTIoWEgwx3n8YPLaO 3Iv5oTGG2jVUUOT7jhWaiyaQcmQNbsptBVmZIdNhnkixLhGKPX6Xyi50ZEclwUAlzTIwxApbe 9uxsyP+ioOWP+wWdnJn98twsYYj0sqQ7yt7r5cRKp0eWzDiMOcHugN8ciGmWAT1b4UcIG7hCN ayGlXVEmXZ3AqUKklRlk9EkxraPkQ8HJwppXgqEOocl5AepOkyCYnHjNDwx2SPmUTp39DG6yv EdTPXmpUX/zkJslQ6Zkcbj+YiMeOINCZCsYCs9jFmMLxAP8uuxGq1wnicb2jQ8a40IKSN/3I2 lHbiEbKD8OcYxUeOGws/6GpE0/3apyHjXPGQkAqT/I6yqIIPwJsVBG2inLakDE4tXSN/gQYJI hDyX/+1iXGkvYVr1GXlCZABgLDJ+inwxk4q1r8dKrQRbQRiYfV9aqZVU6G0Yf5VdvmsOFBjJ3 hJ1OzJ1BFUjaf8UU2LH3VXluiskhtaUFZ4Xpx8/XEPqPRIpelOIiTiLrKrGEaaPgSNS/KfYvM yInt5GaqgLkYFJyDaK1G/bQ/J7Irh188RLj2TTcC99fHW4Wvry2xBYnHUCWOijdevoOhAJuQv ZxfdKnwACJRTf8H6+NrSekT6uSm8GuXZy6dY133MArld/QgsHJp9LItWqymEEpzBOSWt5txZ X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 212.227.17.12 X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.14 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-bounces+ged-emacs-devel=m.gmane.org@gnu.org Xref: news.gmane.org gmane.emacs.devel:196529 Archived-At: phillip.lord@russet.org.uk (Phillip Lord) writes: > >> I am a bit surprised to find that _ needs , in these examples, and I > >> think that it's a bug. > > > > I think it's intentional, and it fits the documentation. > > Not convinced. The documentation says.... > > =E2=80=98(pred numberp)=E2=80=99 is a pattern that simply checks that =E2= =80=98exp=E2=80=99 is a number, > and =E2=80=98_=E2=80=99 is the catch-all pattern that matches anything. > > for example, which made me assume that "_" matches anything. Anything in a backquote is implicitly quoted, and thus should behave like 'VAL matches if the object is =E2=80=98equal=E2=80=99 to VAL. The elements in a backquoted list in a pcase pattern are _not_ interpreted as pcase patterns, unless unquoted. _ is not special here. You also can't use `(1 2 (pred numberp)) as you would expect. Why should _ be different? Michael.