[antlr-interest] ANTLR bug??? ReportError not called on "NonViableAltException"

[Thomas Brandon]

On 8/8/07, Frank Smith <fasmith718 at gmail.com> wrote:
> Hi all.  I recently uncovered a problem with my parser where i'm doing
> something illegal and ReportError is never called.  ANTLRworks' interpreter
> window shows that there is a Nonviable alt, but the breakpoint i put in
> RecognitionError is never reached on code execution.
>
> This is a big problem because I am trying to make my language fail
> immediately on parse errors, but I can't do this if they are never thrown by
> the generated antlr code!
>
> Here is the sample program - you should not be able to put a statement
> outside of a function :
> fun wave main()
>     print "main";
> end fun
> x = 1;
>
> yet this compiles without reporting an error.  However, putting it in
> ANTLRWorks' interpreter shows it to be wrong (which is what i want, darn
> it!)
>
> Here is my entire .g file.  If someone could just past it into their
> antrlworks and explain this discrepancy i would be highly highly
> appreciative.  This is for a project and I need to know if I should pass
> this off as a bug in ANTRL generated code... :-/
>
> Thanks a million times in advance!!!
>      Frank
>
> program    :    (include_stmt)*(fun_decl)+;
I think the problem is that this needs to be:
program    :    (include_stmt)*(fun_decl)+ EOF;
otherwise ANTLR will just decide the first error means the end of what
it needs to parse.
Though the difference of behaviour in the interpreter is still an issue.

Tom.