[climacs-devel] lisp-syntax and parse tables

[Earl J. Wagner]

Hi all,

I've been looking at how to automatically generate the lisp-syntax  
parser from BNF descriptions like S -> form*, etc. To do this, I'm  
integrating a modified version of Mark Johnson's LALR parse table  
generator linked to from here:
http://www.cog.brown.edu/~mj/Software.htm

I have a few questions however
1) What's the rationale behind representing parse states as CLOS  
objects, as opposed to just numbers?
On the one hand this is a little easier to understand when parsing  
breaks, but my intuition is that it introduces a lot of overhead.

2) Is it necessary to interleave lexing and parsing?
It's conventional to have a lexing stage then a parsing stage, but  
because of C's macros and other reasons for C++, that doesn't work  
for those languages. Correct me if I'm wrong, but Lisp seems uniform  
enough that even if you introduce macros or additional syntax, the  
lexer should be able to function independently of the parser.

My inclination is to split current-state into a lexer state and parse  
state. Lexer state will be identified symbolically as is done now and  
the parse state will be represented by state-ids.

-Earl