Klaas-Jan Stol wrote:
Hi,
for sake of completeness, I just updated the Lua wiki with a link to
a Lua 5 grammar for Bison (or Yacc). I'm using this grammar in my
attempt to write a Lua compiler targeting Parrot, the new virtual
machine for Perl6. I'm pretty sure it's complete. Lua has 1
ambiguity, as described in the reference manual, this same ambiguity
is also present in this grammar file. In this file, it is present as
a shift/reduce conflict, resolved by default by a "shift". Adding a
semicolon will result in a "reduce". (this is pretty much the same
behaviour as in original Lua, I think).
kind regards,
klaas-jan stol
If you want a fast Lua parser (compared to a Yacc-ish one), consider
PCCTS. It integrates the Bison/Flex syntaxing too. PCCTS can build a
parser that's comperable in performance to a hand coded top down
recursive parser.
In contrast to Yacc solutions, it does require a LR parser, not an
LALR like Yacc. In LR grammars, the repetitions are on the left, not
the right, ie: expressions, expression, not expression, expressions.
(Just an abstract example because I'm too lazy to go find a real
one... ;-) )
PCCTS is free and open source. Builds on standard C.
http://www.polhode.com/pccts.html
Very highly recommended!
Dave LeBlanc
Seattle, WA USA
