From lojban-out@lojban.org Wed Oct 31 09:30:24 2007 Return-Path: X-Sender: lojban-out@lojban.org X-Apparently-To: lojban@yahoogroups.com X-Received: (qmail 2286 invoked from network); 31 Oct 2007 16:30:24 -0000 X-Received: from unknown (66.218.67.96) by m47.grp.scd.yahoo.com with QMQP; 31 Oct 2007 16:30:24 -0000 X-Received: from unknown (HELO mail7.sea5.speakeasy.net) (69.17.117.9) by mta17.grp.scd.yahoo.com with SMTP; 31 Oct 2007 16:30:23 -0000 X-Received: (qmail 18951 invoked from network); 31 Oct 2007 16:30:23 -0000 X-Received: from chain.digitalkingdom.org ([64.81.66.169]) (envelope-sender ) by mail7.sea5.speakeasy.net (qmail-ldap-1.03) with AES256-SHA encrypted SMTP for ; 31 Oct 2007 16:30:23 -0000 X-Received: from lojban-out by chain.digitalkingdom.org with local (Exim 4.67) (envelope-from ) id 1InGSP-0006Io-W1 for lojban@yahoogroups.com; Wed, 31 Oct 2007 09:30:21 -0700 X-Received: from chain.digitalkingdom.org ([64.81.66.169]) by chain.digitalkingdom.org with esmtp (Exim 4.67) (envelope-from ) id 1InGRy-00066z-Ed; Wed, 31 Oct 2007 09:29:52 -0700 X-Received: with ECARTIS (v1.0.0; list lojban-list); Wed, 31 Oct 2007 09:27:10 -0700 (PDT) X-Received: from nobody by chain.digitalkingdom.org with local (Exim 4.67) (envelope-from ) id 1InGPN-00066t-Jd for lojban-list-real@lojban.org; Wed, 31 Oct 2007 09:27:10 -0700 X-Received: from nf-out-0910.google.com ([64.233.182.188]) by chain.digitalkingdom.org with esmtp (Exim 4.67) (envelope-from ) id 1InGPK-00066a-Ni for lojban-list@lojban.org; Wed, 31 Oct 2007 09:27:09 -0700 X-Received: by nf-out-0910.google.com with SMTP id 4so144326nfv for ; Wed, 31 Oct 2007 09:26:57 -0700 (PDT) X-Received: by 10.86.77.5 with SMTP id z5mr6717170fga.1193848017413; Wed, 31 Oct 2007 09:26:57 -0700 (PDT) X-Received: by 10.86.86.13 with HTTP; Wed, 31 Oct 2007 09:26:57 -0700 (PDT) Message-ID: <925d17560710310926k5485f82fv9191f290fa7bc807@mail.gmail.com> Date: Wed, 31 Oct 2007 13:26:57 -0300 In-Reply-To: <737b61f30710310839w56198f5eid7d5ba0890011812@mail.gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <737b61f30710301744x530646c8q748ccb5190ec3eee@mail.gmail.com> <925d17560710310630te45f3dbs210159dcc8143a6d@mail.gmail.com> <737b61f30710310839w56198f5eid7d5ba0890011812@mail.gmail.com> X-Spam-Score: 0.0 X-Spam-Score-Int: 0 X-Spam-Bar: / X-archive-position: 13893 X-ecartis-version: Ecartis v1.0.0 Errors-to: lojban-list-bounce@lojban.org X-original-sender: jjllambias@gmail.com X-list: lojban-list X-Spam-Score: 0.0 X-Spam-Score-Int: 0 X-Spam-Bar: / To: lojban@yahoogroups.com X-Originating-IP: 69.17.117.9 X-eGroups-Msg-Info: 1:12:0:0:0 X-eGroups-From: "=?ISO-8859-1?Q?Jorge_Llamb=EDas?=" From: "=?ISO-8859-1?Q?Jorge_Llamb=EDas?=" Reply-To: jjllambias@gmail.com Subject: [lojban] Re: PEG left recursive definitions X-Yahoo-Group-Post: member; u=116389790; y=GkKtQEiXDeH5c6MoI4yEJmA6jT9hn4CSDK6Xb1AvXNOHpRki9g X-Yahoo-Profile: lojban_out X-Yahoo-Message-Num: 28371 On 10/31/07, Chris Capel wrote: > > Do you not think that the grammar definition itself would be better > expressed with explicit left-recursion? Yes, I do, for the cases of left associativity. So for example the left recursive: sumti-2 <- (sumti-2 joik-ek)? sumti-3 would reflect the left associativity better than the current: sumti-2 <- sumti-3 (joik-ek sumti-3)* > > expr <- expr '?' expr ':' expr / 'x' > > which would not be allowed in PEG. > > Well, "not allowed" in most implementations of PEG. (Although direct > left recursion *is* rewritten automatically in Pappy.) But since it's > isomorphic (i.e. identical after rewriting) to a non-left-recursive > definition, I don't see why you'd say it's not allowed at all. I probably used the wrong words. I don't know much more about this than what I learned from the Lojban PEG. I meant it would not be allowed in Robin's implementation. mu'o mi'e xorxes To unsubscribe from this list, send mail to lojban-list-request@lojban.org with the subject unsubscribe, or go to http://www.lojban.org/lsg2/, or if you're really stuck, send mail to secretary@lojban.org for help.