[antlr-interest] lexical nondeterminism

howardk at fatdog.com howardk at fatdog.com
Tue Nov 20 19:52:41 PST 2001

Sigh, I hate to bother people with this one. I thought I'd gotten 
reasonably ok at working out nondeterminism problems, but I can't see 
why the following (slightly simplified) lexical grammar isn't
working. antlr is complaining about the production QName. Lookahead
is k=2.

QName:		(NCName COLON)? NCName;

NCName:		( Letter | '_' ) (NCNameChar)*;

NCNameChar:	Letter | Digit | DOT | '-' | '_';

Letter:		'A' .. 'Z';

Here's the message I get:

warning: lexical nondeterminism upon
k==1: 'A' .. 'Z', '_'
k==2: '-','.','0'..'9','A'..'Z','_'
between alts 1 and 2 of block

I know this isn't hard, but I'm going blind (and I'm not even doing 
THAT!) Any help much appreciated,



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