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[lojban] Re: Where is the latest/official PEG grammar?

Bob LeChevalier <lojbab@lojban.org> writes:

> I don't know why those names are used in any particular PEG
> grammar.

...

> For the tag "anaphoracataphora, I suspect that is not a "bug" because
> anaphora and cataphora are identical in term of grammar so it is
> merely a naming convention whether to include some separator between
> the two words or not.  I don't know what construct "openclosed" refers
> to, but likely it also is a conflation of two types of constructs with
> the same grammar.

No, these are not the names of non-terminals in the PEG, they appear in
the text of comments in the PEG.  They should read "anaphora/cataphora",
"open/closed", etc.  It's as if someone did a global
s|([a-zA-Z])/([a-zA-Z])|\1\2| search and replace on the grammar.  The
fact that nobody seems to have noticed these errors strongly suggests
that these PEG versions of the grammar have not been given sufficient
attention.  (doi camxes)

> The latest *official* grammar remains the YACC grammar included in The
> Complete Lojban Language since its publication in 1997. There have
> been attempts to redevelop the grammar in a PEG form, but NONE of the
> PEG grammars has been certified by byfy (or its new successor group)
> as an official replacement for that old one,

What are we waiting for?  Lojban has been around since 1985 bi'o 1987,
yet we still don't have a complete grammar or a correct parser.  The
YACC has received official blessing, but it's not complete.  Handling of
elidable terminators is hand-hacked into the code.  The lexer is also
hand-coded, and implements only a good approximation to Lojban
morphology.  So far, we have neither a complete specification of the
language, nor a fully correct parser.

> My understanding is that they are more-or-less equivalent to the old
> YACC grammar, but I don't know that this equivalence was ever formally
> proven.

Maybe that's what we're waiting for?  A proof that the PEG grammar is
backward-compatible with the YACC?  If so, the second half of Bryan
Ford's thesis paper on PEGs describes how to transform parsing
expressions into other forms which could be compared with the YACC.

For reference, that thesis paper is: http://bford.info/pub/lang/peg.pdf

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