Subject: Re: [lojban] Parsing "na ku" and "na" followed by other things

From: Logical Language Group <[email-masked]>
Date: Tue, 08 May 2001 23:16:10 -0400

At 10:27 PM 05/08/2001 +0100, Richard Curnow wrote:
>I've had a bug report for jbofi'e which identifies an incompatibility
>with the 'official' parser. This seems to be the version that targets
>v2.33 of the Lojban grammar. [I am not aware of any publically visible
>source code for an 'official' parser for v3.00 of the grammar.]
>
>The example is
>
> i mi djica le nu le nu pensi na zekri
>
>which parses on the 'official' parser, but not on jbofi'e. The problem
>has, I think, been discussed at least once on this list - it's that the
>word "na" is shifted as though "na ku" is coming, rather than the bridi
>"pensi" being reduced first.
>
>I've looked into how the official parser handles this, and it looks like
>there's some special logic to recognize "na ku" as a special case, as
>though it's a single token (hence the LALR(1) mechanism in the parser
>doesn't get confused and shift "na" wrongly. Hence "na" followed by
>something else would cause the bridi "pensi" to be reduced in the
>example.)
>
>Is this handling of "na ku" considered current behaviour for the v3.00
>Lojban grammar? I'm asking because the official parser's behaviour for
>this case was never discussed when the "na ku" issue was discussed on
>the list before.
>
>I want to go ahead and fix jbofi'e for this case, but obviously only if
>detecting "na ku" as though it's a single token is still considered
>correct behaviour in grammar v3.00.

Per step 5 in the algorithm stated in the front of grammar.300, all lexer 
lexemes must be inserted before submitting the text to YACC parsing or 
LALR1 will fail. NA+KU must be tagged by lexer_J per rule 950.

lojbab
--
lojbab [email-masked]
Bob LeChevalier, President, The Logical Language Group, Inc.
2904 Beau Lane, Fairfax VA 22031-1303 USA 703-385-0273
Artificial language Loglan/Lojban: http://www.lojban.org