[antlr-interest] Tree walk NullPointerException

Eugene Seliverstov theirix at gmail.com
Sat Nov 25 07:46:15 PST 2006


Hello, all!

Sometimes during work of tree grammar parser NullPointerException is thrown.
Exception happens at "
org.antlr.runtime.tree.CommonTreeNodeStream.walkBackToMostRecentNodeWithUnvisitedChildren
(CommonTreeNodeStream.java :483)" and caused by accessing null element at
top of stack indexStack.
This can appear unexpectedly on different rules, on different input texts. I
think sometimes it's because small lookahead or disambiguation of
 grammar rules, but why it's no detected at code generation time?..

Of course, I can provide grammars if it can help (they are too large to post
here).
Version of antlr - 3.0b5.

Thank you for regards!

-- 
Best regards,
Eugene Seliverstov
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