javacc parseException... lookahead problem?

Question

I'm writing a parser for a very simple grammar in javacc. It's beginning to come together but at the moment I'm completely stuck on this error:

    ParseException: Encountered "" at line 4, column 15.
Was expecting one of:

The line of input in question is z = y + z + 5

and the production that is giving me problems is my expression which get called from varDecl():

<ID> <EQL> expression()

Expression looks like this:

     <VAR> (<PLUS> expression())?| <NUM> (<PLUS> expression())? 
  | call() (<PLUS> expression())?

I'm at a loss as to why I'm getting this error - any insight would be greatly appreciated.

Answer 1

Hm, yes, that's not a very helpful error from JavaCC. What version of JavaCC are you using?

Also, it's difficult to troubleshoot these problems without seeing the full grammar... and although I understand you might not be in a position to post that.