[antlr-interest] Grammar.createLookaheadDFA(): could not even do k=1 for decision 45;

[Erik Kratochvil]

Hi.

I have a parser grammar which would not be processed neither by
antlr-3.0.1 (official release) nor by antlr-3.1b1
(antlr-2008-01-23.10.tar.gz).

antlr-3.0.1 fails with:

error(10):  internal error:
org.antlr.tool.Grammar.createLookaheadDFA(Grammar.java:864): could not
even do k=1 for decision 442

antlr-3.1b1 fails with a little bit more descriptive error:

error(10):  internal error:
org.antlr.tool.Grammar.createLookaheadDFA(Grammar.java:1138): could
not even do k=1 for decision 442; reason: timed out (>1000ms)

on top of that antlr-3.1b1 adds a NullPointerException:

error(10):  internal error: O.g : java.lang.NullPointerException
org.antlr.tool.Grammar.getTokenDisplayName(Grammar.java:2158)
org.antlr.codegen.CodeGenerator.genTokenTypeNames(CodeGenerator.java:823)
org.antlr.codegen.CodeGenerator.genRecognizer(CodeGenerator.java:433)
org.antlr.Tool.generateRecognizer(Tool.java:416)
org.antlr.Tool.process(Tool.java:285)
org.antlr.Tool.main(Tool.java:70)


What precisely does this error(10) mean?

-- 
Erik Kratochvíl