[lojban] Re: PEG grammar issues

["Chris Capel" <pdf23ds@gmail.com>]

On Mon, Jun 16, 2008 at 11:34 AM, Jorge Llambías <jjllambias@gmail.com> wrote:
> On Sun, Jun 15, 2008 at 11:39 PM, Chris Capel <pdf23ds@gmail.com> wrote:
>>
>> First, the top-level production should fail if it can't parse the
>> whole string. Currently 'text' ends with an EOF?, which makes it never
>> fail.
>
> I think that was on purpose: parse as much as you can parse, and
> discard anything unparsable that follows.

Sure, but I think that both behaviors are needed in different
contexts. But it doesn't really matter much--individual parsers will
do what they will.

>> Second, selbri-3 should parse its child selbri-4 into left-associative
>> groups.
>
> The same applies to statement-1, bridi-tail-1 and sumti-2, right?

Don't think so, maybe, and maybe, except that in the last two cases,
the parse tree actually shows them as right-associative, which would
make it harder to fix. But I'm not terribly clear on the grammar (in
the wider sense) here. No to 'statement-1' because I don't think
statement-2's really have associativity, so the correct parse tree
would be flat, and the current parse tree is flat, so it's not broken.
Same thing for bridi-tail-1 and sumti-2--do those really have
associativity? Does it matter which order you interpret the giheks or
jeks?

>> Third, tenses that probably ought to be parsed as part of the bridi
>> are currently being parsed as head terms, because of the term-1
>> production:

>> I'm not exactly sure how this one needs to be
>> fixed, but what about this:
>>
>>   term-1 <- sumti / term-2 / termset / NA-clause KU-clause free*
>>
>>   term-2 <- !gek (tag (sumti / KU-clause free*) / FA-clause free*
>> (sumti / KU-clause? free*) )
>
> That makes it impossible to omit {ku} in other positions as well.
> For example, {mi ka'e pu klama} would fail.
>
> How about "!gek !selbri" instead of just "!gek" in the original rule?

Sounds good to me.

>> Fourth, 'term-sa' only appears to match one term sa under some
>> conditions. For instance, it doesn't match this:
>>
>>   mi ba klama lo sa lo sa do
>>
>> which one might imagine could be said by someone with a stutter.
>> Here's one possible fix:
>>
>>   term-sa <- term-start (!term-1 (sa-word / SA-clause !term-1) )*
>> SA-clause &term-1
>
> SA ought to be ditched or completely reformulated, IMHO.

Well, my suggestion's there for posterity's sake.

Chris Capel
-- 
"What is it like to be a bat? What is it like to bat a bee? What is it
like to be a bee being batted? What is it like to be a batted bee?"
-- The Mind's I (Hofstadter, Dennet)


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