From nobody@digitalkingdom.org Thu Aug 17 14:43:50 2006 Received: with ECARTIS (v1.0.0; list lojban-list); Thu, 17 Aug 2006 14:43:50 -0700 (PDT) Received: from nobody by chain.digitalkingdom.org with local (Exim 4.62) (envelope-from ) id 1GDpeG-0003Bj-LH for lojban-list-real@lojban.org; Thu, 17 Aug 2006 14:43:32 -0700 Received: from rlpowell by chain.digitalkingdom.org with local (Exim 4.62) (envelope-from ) id 1GDpeG-0003Bc-An for lojban-list@lojban.org; Thu, 17 Aug 2006 14:43:32 -0700 Date: Thu, 17 Aug 2006 14:43:32 -0700 To: lojban-list@lojban.org Subject: [lojban] Re: parsing with error detection and recovery Message-ID: <20060817214332.GI17767@chain.digitalkingdom.org> Mail-Followup-To: lojban-list@lojban.org References: <737b61f30608151434h6ed71ec2k123f043c1ad59838@mail.gmail.com> <20060817211332.GH17767@chain.digitalkingdom.org> <925d17560608171439h43b6194eu88cd63845e984bec@mail.gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <925d17560608171439h43b6194eu88cd63845e984bec@mail.gmail.com> User-Agent: Mutt/1.5.12-2006-07-14 From: Robin Lee Powell X-archive-position: 12487 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, Aug 17, 2006 at 06:39:20PM -0300, Jorge Llamb?as wrote: > On 8/17/06, Robin Lee Powell wrote: > >On Tue, Aug 15, 2006 at 04:34:57PM -0500, Chris Capel wrote: > >> So, my question is this: is there an easy way to prove the > >> equivalence of PEG parser A with the parts of parser B that > >> apply only to valid input? > > > >I'm not aware of any way to prove equivalence of any two PEGs, > >ever. > > Surely that's too strong. Given: > > PEG1 > > text <- 'a' / 'b' > > PEG2 > > text <- a / b > a <- 'a' > b <- 'b' > > they can be proven to be equivalent? Oh, probably, but I don't know how. > Maybe what you mean is that there is no known method that will > prove the equivalence or not of any arbitrary pair of PEGs. That is what I meant, yes. -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.