[antlr-interest] booleans in interpreters

[Michael Laszlo]

In my lexer code, my ID pattern picks out keywords and literals.
For example:

ID:	LETTER (LETTER|DIGIT)* {
	...		
	// primitive literals
	else if (getText().equals("true")) { $setType(BOOLEAN); }
	else if (getText().equals("false")) { $setType(BOOLEAN); }
	}

My parser includes this code:

tokens {
	BOOLEAN<AST=BooleanNode>;
	...
}

My intention is to build a true and a false instance of the 
BooleanNode class. The BooleanNode constructor uses getText()
to distinguish the two cases.

However, antlr.Tools complains about nondeterminisms between
rules BOOLEAN and ID. 

I've noticed that if I include an assignment clause in the 
tokens declarations, things work fine. Something like:

tokens {
	BOOLEAN_TRUE="true"<AST=BooleanNode>;
	BOOLEAN_FALSE="false"<AST=BooleanNode>;
	...
}

However, it shouldn't be necessary to define distinct token types
for true and false. 

Any suggestions?

Thanks, Michael