[lojban] Re: gleki xisri'i

[Robin Lee Powell <rlpowell@digitalkingdom.org>]

On Fri, Dec 26, 2008 at 03:50:28AM +0300, Cyril Slobin wrote:
> On Fri, Dec 26, 2008 at 3:22 AM, Cyril Slobin <cyril@slobin.pp.ru>
> wrote:
> 
> > Example of such invalid phrase:
> >
> >  nu le broda broda
> >
> > (Courtesy of Robin; probably he is bored to repeat this again
> > and again, so there is my turn ;-)
> 
> To Robin: after a cup of tea, the problem seems to me worse then
> before. I don't remember the exact CLL wording, but it is some
> informal English prose like "terminators may be omitted unless
> this leads to ambiguity", right? 

Something to that effect, specifically:

    // encloses an elidable terminator, which may be omitted
    (without change of meaning) if no grammatical ambiguity results.

> As a formalization of this informal English prose, we have the
> official yacc-based parser with it's shift over reduce preference,
> right? But this formalization fails in the example above! 

The official yacc-based parser uses magical error productions to
avoid being a real CFG.

> Correct me if I am wrong, but I believe there is one and only one
> way to restore the omitted terminators there:
> 
>   nu le broda KU broda KEI

Seems to me, yes.  Note that "si" can also fix it in interesting
ways.  :)

> Therefore, by definition, there is no ambiguity, and the phrase is
> correct. But the official parser rejects it! So, I think, we
> should either (1) decide that parser is always right, and clarify
> English wording, or (2) make a better parser. Or am I missed
> something?

(1) is already true, actually; the CLL makes it clear that the
official parser wins.

The problem is that there *is* grammatical ambiguity: the sentence
*could* be an error; someone could have forgotten to say "cu brodi"
afterwards, or it's taken out of context or whatever, but
regardless, nu le broda broda KU KEI is perfectly valid, it's just
not a valid Lojban utterance by itself.

Saying that the parser will find *some* valid parse if it exists
strikes me as expanding Lojban rather a lot.  I imagine that
figuring out that "nu le broda broda" means "nu le broda KU broda
KEI" in real time would *really* suck.  I don't think a human could
keep up.

-Robin

-- 
They say:  "The first AIs will be built by the military as weapons."
And I'm thinking:  "Does it even occur to you to try for something
other than the default outcome?" -- http://shorl.com/tydruhedufogre
http://www.digitalkingdom.org/~rlpowell/ *** http://www.lojban.org/


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