Re: AW: Parsing Specific Productions

[Indrek Mandre <indrek@mare.ee>]

Wasn't this answered in the mailing-list just a month ago?
http://www.sable.mcgill.ca/listarchives/sablecc-list/msg00567.html
Or am I missing something?

Regards,
Indrek

Mariusz Nowostawski wrote:

> Hi Patricio
>
> > Let's supose that in certain grammar you have a main production, let's
> > call it P1, and you have an internal production called P2.
> >
> > Due to P2 is part of a bigger production P1, I can only reach it by
> > parsing P1, an example of that is the Java grammar, taking P1 as the
> > production of a class, and P2 the production of a method.
>
> I can see your point. Do you want it in general or just for classes and
> methods (and maybe blocks)?  I do not really know how to do it in general
> sense, but in case of just several such productions, where you know in
> advance what you would like to be able to parse, simply add all your
> productions as alternatives to the top level production.  E.g.
> I have modified a Java grammar because I wanted not only be able to parse:
>
> in File1.java:
>
>  class File1
>  {
>     blah, blah, blah
>  }
>
> but also:
>
> in File2.mariusz_java_script
>
>  {
>   int a = 10;
>   System.out.print(a);
>  }
>
> (to have Java-like scripts in seperate files).
>
> So, the first is just ordinary goal - compilation_unit production, and for
> the second to parse I have added:
>
> compilation_unit =
>     package_declaration? import_declaration* type_declaration* |
>     {script} block ;
>
> so I can get the second thing parsed as well, as
>                                          goal - script_compilation_unit
>
> It should work for classes/methods as well in your case. It should work
> for most cases, where there is no conflict between alternatives in the
> top most production, and, the only not nice thing is that you need to
> know in advance what productions you can have as the top most
> productions and you need to specify them all.
>
> Hope that will help you to move on with the project,
>
> best regards
> Mariusz