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: Question on pcase Date: Mon, 26 Oct 2015 17:07:32 +0100 Message-ID: <87lhapd35n.fsf@web.de> References: <871tcngdv2.fsf@gmail.com> <87k2qe1u09.fsf@web.de> <83r3kmrtat.fsf@gnu.org> <87r3kl22zk.fsf@web.de> <837fmdzpf2.fsf@gnu.org> <87oafp659p.fsf@web.de> <831tclzly9.fsf@gnu.org> <87fv115t20.fsf@web.de> <87io5tzkt8.fsf@gmail.com> NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: text/plain X-Trace: ger.gmane.org 1445875694 31614 80.91.229.3 (26 Oct 2015 16:08:14 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Mon, 26 Oct 2015 16:08:14 +0000 (UTC) To: emacs-devel@gnu.org Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Mon Oct 26 17:07:57 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 1ZqkJP-0007bG-Uu for ged-emacs-devel@m.gmane.org; Mon, 26 Oct 2015 17:07:56 +0100 Original-Received: from localhost ([::1]:53860 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZqkJP-0001F2-F4 for ged-emacs-devel@m.gmane.org; Mon, 26 Oct 2015 12:07:55 -0400 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:43462) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZqkJM-0001Ex-CI for emacs-devel@gnu.org; Mon, 26 Oct 2015 12:07:53 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ZqkJI-0003ro-CB for emacs-devel@gnu.org; Mon, 26 Oct 2015 12:07:52 -0400 Original-Received: from plane.gmane.org ([80.91.229.3]:41116) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZqkJI-0003rE-5Z for emacs-devel@gnu.org; Mon, 26 Oct 2015 12:07:48 -0400 Original-Received: from list by plane.gmane.org with local (Exim 4.69) (envelope-from ) id 1ZqkJD-0007Pm-J9 for emacs-devel@gnu.org; Mon, 26 Oct 2015 17:07:43 +0100 Original-Received: from ip-90-186-3-146.web.vodafone.de ([90.186.3.146]) by main.gmane.org with esmtp (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Mon, 26 Oct 2015 17:07:43 +0100 Original-Received: from michael_heerdegen by ip-90-186-3-146.web.vodafone.de with local (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Mon, 26 Oct 2015 17:07:43 +0100 X-Injected-Via-Gmane: http://gmane.org/ Original-Lines: 36 Original-X-Complaints-To: usenet@ger.gmane.org X-Gmane-NNTP-Posting-Host: ip-90-186-3-146.web.vodafone.de User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/25.0.50 (gnu/linux) Cancel-Lock: sha1:OliiluLV3LbKCa0tLdmn1iPk0Co= X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. X-Received-From: 80.91.229.3 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:192662 Archived-At: Hi Oleh, will read the rest of your post carefully later, but > (macroexpand '(pcase test > (`(,foo . ,baz) > (cons baz foo)))) > ;; => > ;; (if (consp test) > ;; (let* ((x (car test)) > ;; (x (cdr test))) > ;; (let ((baz x) > ;; (foo x)) > ;; (cons baz foo))) > ;; nil) > > The macroexpanded code returns (2 . 2) when evaluated. This I don't > understand. This is due to printing again. With the default settings, (compose print read) (so to say) is not guaranteed to preserve semantics of code. Try with (setq print-gensym t) (setq print-circle t) as I had suggested in a prior post. Regards, Michael.