[antlr-interest] tree construction, associative operators, NullPointerException

[Gavin Lambert]

At 01:39 8/08/2008, Johan Grande wrote:
 >The solution I use until now (non binary trees) is not at all
 >satisfying, because not only I would have binary trees, but my
 >"solution" doesn't work for rules with more than one operator, 
for
 >example :
 >,----
 >| equalityExpression
 >|     :   instanceOfExpression ( ('==' | '!=') 
instanceOfExpression
 >)*
 >|     ;
 >`----

If you change that to use ('==' | '!=')^ (note the extra caret) 
then the operator will become the root node -- this will also 
automatically produce a left-associative binary tree.