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Re: [lojban] questions about peg grammar

On Fri, Oct 29, 2010 at 03:36:09PM -0400, Luke Bergen wrote:
>    Ok, so I'm trying to get a feel for how the peg grammar handles lujvo so
>    that I can make my parser be as close to the real deal as possible (i.e.
>    not a sloppy hack). I have a question though. I think the relevant section
>    that I want to understand is the following, correct?
>    ;-----------------------------------------------------------------------------------------------------------------------------------------
>    lujvo <- !gismu !fuhivla !cmavo initial-rafsi* brivla-core
>    brivla-core <- fuhivla / gismu / CVV-final-rafsi / stressed-initial-rafsi
>    short-final-rafsi
>    stressed-initial-rafsi <- stressed-extended-rafsi / stressed-y-rafsi /
>    stressed-y-less-rafsi
>    initial-rafsi <- extended-rafsi / y-rafsi / !any-extended-rafsi
>    y-less-rafsi
>    any-extended-rafsi <- fuhivla / extended-rafsi / stressed-extended-rafsi
>    ;-----------------------------------------------------------------------------------------------------------------------------------------
>    Now, I may be reading this incorrectly, but wouldn't this mean that an
>    initial rafsi followed by a fuhivla would be considered a lujvo? i.e.
>    {bracidrspageti}?
> 

This is a bit tricky.

Look at the early part of the lujvo definition, and you can see
there is a predicate-not operation saying "it can't have a fuhivla"
(That is the !fuhivla).

So when the brivla-core matches, even through brivla-core is capable
of having a fuhivla, it won't ever have one in this case, because
the earlier predicate-not operation in the lujvo nonterminal won't let
one be there.

-Alan
-- 
.i ko djuno fi le do sevzi

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