[antlr-interest] Parser generation takes hours

Jean-Pierre LAMBERT jp.raven at worldonline.fr
Wed Jan 6 03:52:08 PST 2010

Thank you for the feedback. If find very interesting that basically 
we've done the same kind of task (translating a LR parser to ANTLR) and 
then we encounter the same problem doing it.

Furthermore it's very encouraging to know that you could overcome it.

I have already started to remove parts of the grammar and the problem is 
still there.

Your advice is very helpful, thanks again.


Le 06/01/2010 07:42, Gokulakannan Somasundaram a écrit :
> Hi Jean,
>           I faced up with a similar issue, when i tried the migration
> of  a LR parser. But it's definitely because of recursion stuffs. The
> way i removed is sort of layman stuff, but thought of just informing you.
>           Try to split the grammar into multiple sections(group of
> rules) and try to add them one-by-one. You don't need to wait till the
> errors are emitted. As soon as the parser generation takes more than 3-4
> mins, just stop the generation. The last section, which resulted in the
> increase most probably contains the problematic code. Bear with me, if
> this approach looks very awkward.
> Thanks,
> Gokul.
> On Tue, Jan 5, 2010 at 8:22 PM, Jean-Pierre LAMBERT
> <jp.raven at worldonline.fr <mailto:jp.raven at worldonline.fr>> wrote:
>     Hello everybody,
>     I'm currently rewriting a LR parser to be used for ANTLR. As a result,
>     ANTLR works literaly for hours before it outputs errors about my
>     grammar.
>     My work is not finished; I have removed all left-recursions but I still
>     have to do left-factorisations. The problem being that since ANTLR works
>     for hours before I get the errors, it isn't very practical for me to fix
>     the grammar.
>     Do you have any suggestions in this case? What could be done so that
>     ANTLR would take only dozen of minutes? Is there something capital that
>     I missed about ANTLR and LL grammars? How should be written ANTLR rules
>     to avoid such a problem?
>     Thanks in advance, any adice will be welcome.
>     JP
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