[antlr-interest] Left-factoring and recursion

Nigel Sheridan-Smith nbsherid at secsme.org.au
Sun Jan 9 14:38:24 PST 2005

Hi everyone,

I was wondering if there are any tools out there that help with
left-factoring, or converting from LALR/LR to LL(k)? 

I am trying to do a Structure of Management Information (SMI) grammar for
networking devices. I tried the ANTLR ASN.1 grammar that already exists, but
it had a few non-determinisms and the like, so I started to do my own since
it looked pretty messy to fix up. However, now I have even more
non-determinisms because the X.680-683 standards seem to favour
left-recursion (like just about everyone else). So I'm faced with the huge
and complicated left-factoring task, or I can switch back to the existing
ASN.1 grammar and try and extend that.

Any ideas? 

I found a few links from ANTLR/PCCTS users:


But these are just very high-level. What I really need is a tool that either
helps in clarifying what the non-determinisms are given a particular ANTLR
grammar, or even attempts to left-factor on its own.



Nigel Sheridan-Smith
PhD research student

Faculty of Engineering
University of Technology, Sydney
Phone: 02 9514 7946
Fax: 02 9514 2435 

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