[antlr-interest] Bad grammar?

[rkevinburton at charter.net]

I am relatively new to ANTLR so as suggested I am starting with one of the "known" grammars. I decided to start with the JavaScript grammar by Chris Lambrou. It failed to parse what I think is valid JavaScript. So I decided to try to debug the problem and I found (in ANTLRWorks) that the following rule is not right:

formalParameterList
	: '(' (LT!* Identifier ( ',' LT!* Identifier)*)?  ')'
	;

If in ANTLRWorks I start at that rule and with the interpreter try '(a,b)' I get:

'(' FailedPredicateException(formalParameterList, {synpred16}?)

I am not able right now to debug it further. What is wrong with this rule?

Thank you.

Kevin