[antlr-interest] On the Importance of Parentheses in Lexer Rules

[Randall R Schulz]

Hi,

I figured out the bizarre (to me, anyway) behavior of my lexer rules and 
parser rules that directly reference lexer rules. E.g., it turns out 
these two are very different:

name
	:	( AtomicWord )
	|	( SingleQuoted )
	|	( UnsignedInteger )
	;

name
	:	AtomicWord
	|	SingleQuoted
	|	UnsignedInteger
	;


By parenthesizing all my lexer alternatives, my parser now is "working." 
(I use the scare quotes because it's really too early to claim that, 
but I'm certain I'm much closer than I was. I can get a successful 
parse of much of my input corpus.)


Randall Schulz