From mboxrd@z Thu Jan 1 00:00:00 1970 Path: main.gmane.org!not-for-mail From: Oliver Scholz Newsgroups: gmane.emacs.help Subject: Re: rx vs sregex - a "match" to the death Date: Mon, 06 Oct 2003 09:25:03 +0200 Sender: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane.org@gnu.org Message-ID: References: NNTP-Posting-Host: deer.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit X-Trace: sea.gmane.org 1065425481 32566 80.91.224.253 (6 Oct 2003 07:31:21 GMT) X-Complaints-To: usenet@sea.gmane.org NNTP-Posting-Date: Mon, 6 Oct 2003 07:31:21 +0000 (UTC) Original-X-From: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane.org@gnu.org Mon Oct 06 09:31:18 2003 Return-path: Original-Received: from monty-python.gnu.org ([199.232.76.173]) by deer.gmane.org with esmtp (Exim 3.35 #1 (Debian)) id 1A6Ppu-0001Ll-00 for ; Mon, 06 Oct 2003 09:31:18 +0200 Original-Received: from localhost ([127.0.0.1] helo=monty-python.gnu.org) by monty-python.gnu.org with esmtp (Exim 4.24) id 1A6Ppi-00037V-Gn for geh-help-gnu-emacs@m.gmane.org; Mon, 06 Oct 2003 03:31:06 -0400 Original-Path: shelby.stanford.edu!newsfeed.stanford.edu!news-spur1.maxwell.syr.edu!news.maxwell.syr.edu!newsfeed.icl.net!newsfeed.fjserv.net!newsfeed.freenet.de!fu-berlin.de!uni-berlin.de!dialin-145-254-136-065.arcor-ip.NET!not-for-mail Original-Newsgroups: gnu.emacs.help Original-Lines: 31 Original-NNTP-Posting-Host: dialin-145-254-136-065.arcor-ip.net (145.254.136.65) Original-X-Trace: news.uni-berlin.de 1065425181 16365004 145.254.136.65 (16 [87814]) X-Attribution: os X-Face: "HgH2sgK|bfH$; PiOJI6|qUCf.ve<51_Od(%ynHr?=>znn#~#oS>",F%B8&\vus),2AsPYb -n>PgddtGEn}s7kH?7kH{P_~vu?]OvVN^qD(L)>G^gDCl(U9n{:d>'DkilN!_K"eNzjrtI4Ya6; Td% IZGMbJ{lawG+'J>QXPZD&TwWU@^~A}f^zAb[Ru;CT(UA]c& User-Agent: Gnus/5.1002 (Gnus v5.10.2) Emacs/21.3.50 (windows-nt) Cancel-Lock: sha1:TsQSFnW2C7Qs6vr1PipF9hNZ/wM= Original-Xref: shelby.stanford.edu gnu.emacs.help:117080 Original-To: help-gnu-emacs@gnu.org X-BeenThere: help-gnu-emacs@gnu.org X-Mailman-Version: 2.1.2 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 Xref: main.gmane.org gmane.emacs.help:13008 X-Report-Spam: http://spam.gmane.org/gmane.emacs.help:13008 Martin Stone Davis writes: [...] > While I was comparing the two functions, I could not find if/how rx > handles numbered backreferences. It's done in sregex like this: > > ;; (sregexq (group (or "Go" "Run")) > ;; ", Spot, " > ;; (backref 1)) => "\\(Go\\|Run\\), Spot, \\1" > > How do you do the same using rx? [...] Well, you could use (regexp "\\1"), but this is of course not satisfying. I am not aware of any other way to use backrefs with `rx'. However, I was not aware that you actually can use backrefs within a regexp. I tried (progn (looking-at "\\w+") (forward-char 1) (re-search-forward "\\0" nil t)) But that did not lead to the result that you would expect if backrefs are/were supported within regexps. Could you provide an example where this is meaningful? Oliver -- 15 Vendémiaire an 212 de la Révolution Liberté, Egalité, Fraternité!