From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: Olaf Rogalsky Newsgroups: gmane.emacs.help Subject: understanding backquote Date: Tue, 02 Jun 2015 21:17:37 +0200 Message-ID: <87mw0hly26.fsf@aol.de> References: <87vbf65jem.fsf@free.fr> NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: text/plain X-Trace: ger.gmane.org 1433272693 30832 80.91.229.3 (2 Jun 2015 19:18:13 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Tue, 2 Jun 2015 19:18:13 +0000 (UTC) To: help-gnu-emacs@gnu.org Original-X-From: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane.org@gnu.org Tue Jun 02 21:18:02 2015 Return-path: Envelope-to: geh-help-gnu-emacs@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 1YzrhF-0005im-Jd for geh-help-gnu-emacs@m.gmane.org; Tue, 02 Jun 2015 21:17:57 +0200 Original-Received: from localhost ([::1]:60520 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YzrhF-00044m-2A for geh-help-gnu-emacs@m.gmane.org; Tue, 02 Jun 2015 15:17:57 -0400 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:48293) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Yzrh4-00044g-Kj for help-gnu-emacs@gnu.org; Tue, 02 Jun 2015 15:17:47 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Yzrh1-00005U-Bq for help-gnu-emacs@gnu.org; Tue, 02 Jun 2015 15:17:46 -0400 Original-Received: from omr-m09.mx.aol.com ([64.12.143.82]:48904) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Yzrh1-0008Vw-6m for help-gnu-emacs@gnu.org; Tue, 02 Jun 2015 15:17:43 -0400 Original-Received: from mtaout-mbe02.mx.aol.com (mtaout-mbe02.mx.aol.com [172.26.254.174]) by omr-m09.mx.aol.com (Outbound Mail Relay) with ESMTP id E40207058DD1F for ; Tue, 2 Jun 2015 15:17:40 -0400 (EDT) Original-Received: from blaubaer (p5DD06311.dip0.t-ipconnect.de [93.208.99.17]) (using TLSv1 with cipher DHE-RSA-AES128-SHA (128/128 bits)) (No client certificate requested) by mtaout-mbe02.mx.aol.com (MUA/Third Party Client Interface) with ESMTPSA id 0FEB5380000A9 for ; Tue, 2 Jun 2015 15:17:39 -0400 (EDT) x-aol-global-disposition: G DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=mx.aol.com; s=20140625; t=1433272660; bh=Rj4HWWC15/8RoAEYHVkwOFKXqJybS6zBclN4HZTFTQo=; h=From:To:Subject:Message-ID:Date:MIME-Version:Content-Type; b=IXhvmJR3WUk7kqCde+TPeW4jrSERX9wB0JoU/70ip8h7D2sn1gEystki94YHbt9Fg YBey2JCkMJ0ha6QLe9Zs+hvFLJJUFXaxuHZqQNmrfMcw36LIiaG1m9OItmIhRSspb0 onHmpfADekYWTiavJ1ZcACZSsRebSMUVmVL/1w1E= x-aol-sid: 3039ac1afeae556e01537481 X-AOL-IP: 93.208.99.17 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.4.x-2.6.x [generic] X-Received-From: 64.12.143.82 X-BeenThere: help-gnu-emacs@gnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: Users list for the GNU Emacs text editor List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane.org@gnu.org Original-Sender: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane.org@gnu.org Xref: news.gmane.org gmane.emacs.help:104718 Archived-At: Hi, I have problems in understanding the semantics of backquote. Consider the following function: (defun test () `,(* (+ 1 2) (+ 3 4))) Now let's have a look at the defintion of the symbol: (symbol-function 'test) => (lambda nil (* (+ 1 2) (+ 3 4))) Huhh??? I was thinking, that the above definition is equivalent to the following: (defun test () 21) Ok, this was unexpected, but perhaps the compiler does it "right": (disassemble (byte-compile 'test)) => byte code: args: nil 0 constant 21 1 return Yes, it does. It is only, that I suspect, that this has nothing to do with backquotes, but rather with constant folding optimization. Can anybody explain this to me? Thanks, Olaf