Subject: Re: [lojban] the formal grammars' utility

From: Richard Curnow <[email-masked]>
Date: Sun, 22 Jul 2001 21:43:15 +0100

Apologies for following up a week late - I've been on vacation!

On Sat, Jul 14, 2001 at 12:46:59PM -0400, Bob LeChevalier (lojbab) wrote:
> At 04:40 PM 07/14/2001 +0100, And Rosta wrote:
> 
> >3. Has anybody created a more succinct but unabbreviated (and, ideally,
> >more intuitive) version of the YACC grammar?
> 
> You just said why people use the EBNF. If the YACC grammar could be more 
> succinct, we would. The EBNF covers the whole language, so it is more 
> succinct and unabbreviated. Its weakness is that it is not proven 
> equivalent to the YACC, so mistakes in obscure places could still surface.
> 

When I created the yacc/bison input for jbofi'e, I deliberately worked
from the EBNF file rather than John Cowan's yacc input file. My hope
was that I would have an independent yacc grammar, and in the long term
this would help us find differences between the ENBF and official yacc
version. 

During jbofihe's lifetime, remarkably few goofs have been found. Even
then, the problems have tended to be more with the pre-parsing stage;
the most recently found fault was that "na ku" has to be pre-parsed to
appear as a single token to the yacc stage.

The above is a rather hubristic view, of course, since most Lojban texts
do not exploit the more esoteric parts of the grammar or combinations
thereof at all. A project I really want to do is to

1. get the "official" v3.00 parser building on Linux
2. complete a random Lojban sentence generator I have which is 1/2
finished
3. write some scripting to feed random sentences to the official parser
and jbofihe in parallel, to find cases where the parsers disagree on
legality.

(I'd begin with allegedly legal sentences and then find subtle ways of
corrupting them.)

Unfortunately, this job has been "pending" for quite some time now.

-- 
R.P.Curnow,Weston-super-Mare,UK |lo samskiro'a cu simsa lo'e glefau
http://www.rrbcurnow.freeuk.com/ |isa'e le xamgu cu tcetcexau ije
[email-masked] |le xlali cu xagmau lenu nomei