Asp Forum - Re: rex & racc vs. ruby-lex & ruby-yacc

Luke A. Kanies

11/16/2006 8:18:00 PM

On Nov 7, 2006, at 4:32 AM, Ryan Hanks wrote:

> Hi,
>
> I'm new to lex and yacc and trying to use one of their ruby
> derivatives to
> build a parser for level 2 cascading style-sheets (CSS2). I'm having
> trouble deciding whether to use rex & racc or ruby-lex & ruby-
> yacc. Can
> someone help me out by explaining to me the ramifications of choosing
> between these two? Does anyone have a particular preference for
> one over
> the other?

I made my decision a long time ago (at least 3+ years), and I don't
remember my exact reasoning. However, I do have two racc parsers
available for your perusal if you're interested, and one of them is
pretty complicated.

I've got a simple Nagios parser in my project named naginator[1], and
a pretty complicated one in Puppet[2]. For Puppet, I used StrScan to
make a lexer, which has so far worked pretty well; for Nagios, I just
wrote a moderately crappy token() method that did the lexing for me.

I know this doesn't help you specifically decide between any of them,
but at least it's some code you can look at, which is more than I had
when I made my decision (I wrote Naginator about 2 years before I
wrote Puppet's parser, and when I went to write Puppet's parser,
Naginator's was the only example I could find).

I'd be glad to answer any follow-on questions about them.

I did look at Antlr and Rockit or whatever they're called, but again,
I don't remember why I chose against them. I'm sure it was at least
partially because I was already pretty familiar with Lex/Yacc-style
grammars.

1 - http://reducti.../cgi-bin/naginator.cgi/browser/...
nagios/grammar.ry
2 - http://reducti.../cgi-bin/puppet.cgi/browser/...
puppet/parser/grammar.ra

--
Luke Kanies
http://m... | http://reducti... | 615-594-8199

comp.lang.ruby

Re: rex & racc vs. ruby-lex & ruby-yacc

Luke A. Kanies

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