From nobody@digitalkingdom.org Wed Oct 31 09:27:10 2007 Received: with ECARTIS (v1.0.0; list lojban-list); Wed, 31 Oct 2007 09:27:10 -0700 (PDT) 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 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 Received: by nf-out-0910.google.com with SMTP id 4so144326nfv for ; Wed, 31 Oct 2007 09:26:57 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=beta; h=domainkey-signature:received:received:message-id:date:from:to:subject:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references; bh=vNNs2DchS7b+4Tgk5GW1+Oga6NVhHOrV94cA0kyRBRk=; b=PpPXxsJQjazoQ/4ei4kU9SgEaj9ev0fYE/48Qg6OFmrHqLHLCbCkr0z9PHNWZOFA3t53x65mZoRaMrltiqa4sH1D5G+dYaKJlTFcaF9nKetnL2DCd15sl/DCgFHY7yWMrKZzKjIhlt0Q35DkA6FB9fuL9g5975B+cdhWXTXkBmE= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=beta; h=received:message-id:date:from:to:subject:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references; b=q1oLarh87m7H/G/ALKtoX6pO+X7YXDl9KhNv3XFbEtaysSIPVM+n2SvR4d43jdKPATh7TiX6erYXmEmxPQZ415/+zexfrvqqg7wL99LIanSoRpTlQr/RDWHdI0exJnyrG9Lw/Hm9fisVtUhiDPq2zUUX85SgLhgSf1tM1G2n+j8= Received: by 10.86.77.5 with SMTP id z5mr6717170fga.1193848017413; Wed, 31 Oct 2007 09:26:57 -0700 (PDT) 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 From: "=?ISO-8859-1?Q?Jorge_Llamb=EDas?=" To: lojban-list@lojban.org Subject: [lojban] Re: PEG left recursive definitions 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 Sender: lojban-list-bounce@lojban.org Errors-to: lojban-list-bounce@lojban.org X-original-sender: jjllambias@gmail.com Precedence: bulk Reply-to: lojban-list@lojban.org X-list: lojban-list 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.