From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: lee Newsgroups: gmane.emacs.help Subject: Re: replacing a function with another one Date: Sat, 15 Mar 2014 20:51:23 +0100 Organization: my virtual residence Message-ID: <878usbw890.fsf@yun.yagibdah.de> References: <87vbvofsi6.fsf@yun.yagibdah.de> <87bnxgs4r9.fsf@web.de> <87lhwj1cfz.fsf@yun.yagibdah.de> <87zjkz6vd5.fsf@web.de> <8738ir161u.fsf@yun.yagibdah.de> <87eh2b6nfm.fsf@web.de> <87r46anab5.fsf@yun.yagibdah.de> <87wqg2u77k.fsf@web.de> <87pplugjh6.fsf@yun.yagibdah.de> <8738ipd2kh.fsf@web.de> <87y50gj1uf.fsf@yun.yagibdah.de> <874n34ticd.fsf@web.de> <87bnxcrloa.fsf@web.de> <87vbvjmq0h.fsf@yun.yagibdah.de> <87siqmy39r.fsf@web.de> 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 1394918162 25858 80.91.229.3 (15 Mar 2014 21:16:02 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Sat, 15 Mar 2014 21:16:02 +0000 (UTC) To: help-gnu-emacs@gnu.org Original-X-From: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane.org@gnu.org Sat Mar 15 22:16:11 2014 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 1WOvwB-00054v-DC for geh-help-gnu-emacs@m.gmane.org; Sat, 15 Mar 2014 22:16:11 +0100 Original-Received: from localhost ([::1]:51217 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WOvwA-0000Xa-Sj for geh-help-gnu-emacs@m.gmane.org; Sat, 15 Mar 2014 17:16:10 -0400 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:41123) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WOvuo-0006Jw-Ho for help-gnu-emacs@gnu.org; Sat, 15 Mar 2014 17:14:51 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1WOvue-0002lg-61 for help-gnu-emacs@gnu.org; Sat, 15 Mar 2014 17:14:46 -0400 Original-Received: from client-194-42-186-216.muenet.net ([194.42.186.216]:36524 helo=yun.yagibdah.de) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WOvud-0002jd-Mt for help-gnu-emacs@gnu.org; Sat, 15 Mar 2014 17:14:36 -0400 Original-Received: from lee by yun.yagibdah.de with local (Exim 4.80.1) (envelope-from ) id 1WOvuT-0005js-IU for help-gnu-emacs@gnu.org; Sat, 15 Mar 2014 22:14:25 +0100 In-Reply-To: <87siqmy39r.fsf@web.de> (Michael Heerdegen's message of "Thu, 13 Mar 2014 08:19:12 +0100") User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.3.50 (gnu/linux) Mail-Followup-To: help-gnu-emacs@gnu.org X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 194.42.186.216 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:96524 Archived-At: Michael Heerdegen writes: > lee writes: > >> and it doesn=C2=B4t work because end-marker is undefined despite I just >> defined it :( So I have >> >> >> (let ((end-marker (concat "^" comment-start lsl-hi-lock-patterns-end= -marker))) >> (let ((marker-pos (re-search-forward end-marker (point-max) t))) >> (do-something))) >> > > The functionality you want, and that you reached with the nested `let', > is exactly what `let*' does. When I was learning LISP, I was also > confused about `let'. Standard `let' first evaluates all > expressions, then binds the variables, so in works "parallel" - see Ah! Finally I understand what the difference is! What is the point of having two variations of `let'? > [...] >> (let ((patterns nil)) >> (while (< (point) marker-pos) >> (setq patterns (append (read (current-buffer)) patterns))) >> (setq patterns patterns))))))) >> >> >> I need this function to return `patterns'. Without the last line, it >> seems to return nil because the setq is enclosed in the while. > > `let' returns the value returned by the last body expression (in > particular, that isn't necessarily the value of the variable `patterns' > in your example!). And `while' always returns nil (strictly speaking, > the return value isn't documented, so don't rely on it at all). So this > is what you want: > > (let ((patterns nil)) > (while (< (point) marker-pos) > (setq patterns (append (read (current-buffer)) patterns))) > patterns) Thank you --- I only found that out yesterday. It makes sense when you think that a symbol stands for itself --- which is probably not correct, but I just think of it as that the variable stands for itself and can be returned like that. --=20 Knowledge is volatile and fluid. Software is power.