From nobody@digitalkingdom.org Thu Jul 13 09:58:53 2006 Received: with ECARTIS (v1.0.0; list lojban-list); Thu, 13 Jul 2006 09:58:54 -0700 (PDT) Received: from nobody by chain.digitalkingdom.org with local (Exim 4.62) (envelope-from ) id 1G14WH-0005ZX-Sg for lojban-list-real@lojban.org; Thu, 13 Jul 2006 09:58:33 -0700 Received: from rlpowell by chain.digitalkingdom.org with local (Exim 4.62) (envelope-from ) id 1G14WH-0005ZQ-Jw for lojban-list@lojban.org; Thu, 13 Jul 2006 09:58:33 -0700 Date: Thu, 13 Jul 2006 09:58:33 -0700 To: lojban-list@lojban.org Subject: [lojban] Re: Is Lojban a CFG? (was Re: [lojban-beginners] Re: Enumerating in Lojban) Message-ID: <20060713165833.GP18359@chain.digitalkingdom.org> Mail-Followup-To: lojban-list@lojban.org References: <20060713003616.GD18359@chain.digitalkingdom.org> <20060713013545.GF18359@chain.digitalkingdom.org> <20060713025542.GH18359@chain.digitalkingdom.org> <925d17560607130709u3fef60c5ubd8f638c795685c0@mail.gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <925d17560607130709u3fef60c5ubd8f638c795685c0@mail.gmail.com> User-Agent: Mutt/1.5.11+cvs20060403 From: Robin Lee Powell X-archive-position: 12178 X-ecartis-version: Ecartis v1.0.0 Sender: lojban-list-bounce@lojban.org Errors-to: lojban-list-bounce@lojban.org X-original-sender: rlpowell@digitalkingdom.org Precedence: bulk Reply-to: lojban-list@lojban.org X-list: lojban-list On Thu, Jul 13, 2006 at 11:09:49AM -0300, Jorge Llamb?as wrote: > If I'm not mistaken, for any CFG, there is a PEG that will accept > all and only the strings generated by that CFG. I don't think anyone's really sure about that. > If that's correct, then what Jonathan wants (a CFG for Lojban) is > compatible with what Robin wants (a PEG for Lojban). Not really. What I want is something that parses Lojban as it's currently defined. I care not at all what formalism does so, as long as there is a pure formalism for it. What Jonathan wants is a CFG, which cannot parse Lojban as it is currently defined. In particular, there is probably not any pure CFG that will reject "le nu le broda brode brodi". > At least in principle, because maybe the required PEG might be way > too complicated to write. Or maybe not, we can at least try. Erm. camxes is a PEG that parses Lojban as currently defined. You helped build it... Perhaps you meant CFG there? > I think this is, simplifying, the kind of thing we would need the > PEG to do in order to handle the {li pa pa pa pa moi} example: The PEG already handles it just fine: it barfs, as it should. That string isn't valid Lojban. > Current PEG rules: > > sentence <- sumti* selbri sumti* > selbri <- number MOI > sumti <- LI number LOhO? > number <- PA+ > > Possible modification to make it context-free: > > sentence <- sumti* selbri sumti* > selbri <- moi-number MOI > sumti <- LI li-number LOhO? > li-number <- PA (PA !MOI)* > moi-number <- PA+ I don't know what language that encodes, but it's not Lojban as I currently understand Lojban to be defined. My reading of it is that it makes {li pa pa pa pa moi} equivalent to {li pa pa pa boi pa moi}. > But I don't know how hard it would be to modify the whole PEG so > that it fully corresponds to a CFG. I don't see the point of doing so; if we're going to make a CFG, we should use CFGs to do so, no make a CFG-alike PEG. I just don't see the point of butchering Lojban to make a CFG that encodes a language that is almost, but not quite, Lojban. -Robin -- http://www.digitalkingdom.org/~rlpowell/ *** http://www.lojban.org/ Reason #237 To Learn Lojban: "Homonyms: Their Grate!" Proud Supporter of the Singularity Institute - http://singinst.org/ 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.