[pro] Is cl-yacc going to cut it?

Scott L. Burson Scott at sympoiesis.com
Fri Feb 4 20:39:40 UTC 2011


On Thu, Feb 3, 2011 at 10:33 PM, Matthew D. Swank <akopa at charter.net> wrote:
> It seems (from my admittedly limited search) that this is not a common
> modification of yacc.  Before I start bugging the maintainer about my
> changes, I want to know: am I abusing yacc?

I've had to do that kind of thing for parsing languages like Cobol
that were designed before the advent of formal parsing theory.

It is an abuse in the sense that it makes it harder to say formally
exactly what language you're parsing, but hey, you do what you have to
do in this business :-)

My own pet parser generator project is a CL reimplementation of Adam
Megacz' Scannerless Boolean Parser:
http://research.cs.berkeley.edu/project/sbp/

Scannerless parsing obviates the kind of games you're having to play
by integrating the lexer into the grammar.  Boolean grammars are more
expressive than context-free grammars.  Both of these things are cool.
 What you don't get in this framework, though, is a proof that your
grammar is unambiguous.

My reimplementation is not far enough along to release, alas, nor do I
really have any time to work on it.  Maybe later this year...

-- Scott




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