[antlr-interest] Decision can match input such as ...using multiple alternatives: 1, 2

[Gavin Lambert]

At 06:51 25/04/2008, elekis wrote:
 >singlePragma: t1=T_Ident
 >			(  T_LParent 	( literal | desigElement (T_Comma 
desigElement)*)
 >			  	(T_Comma ( literal | desigElement (T_Comma 
desigElement)*))
 >			  T_RParent )? T_SemiColon;
 >
 >I have the followed warning
 >
 >warning(200): Pyaflplug.g:35:42: Decision can match input such 
as
 >"T_Comma T_Comma" using multiple alternatives: 1, 2
 >As a result, alternative(s) 2 were disabled for that input

At a guess, 'desigElement' contains a T_Comma, so ANTLR is warning 
you that it's ambiguous with its surroundings.  It's hard to say 
for sure without seeing more of the grammar.

(And you've got a common subexpression there; you probably ought 
to factor it out.)