[antlr-interest] Re: changing a token type at the parser level
Chris Black
cblack0 at yahoo.com
Fri May 14 15:53:26 PDT 2004
--- In antlr-interest at yahoogroups.com, Mark Lentczner <markl at g...> wrote:
> > Unfortunately, whenever I have an empty rule like:
> >
> > empty: ;
> >
> > in my parser, the generated java does not compile since it comlains
> > about an unreachable catch block since an empty rule will not throw a
> > RecognitionException:
>
> > Any ideas?
> How'z'bout:
>
> empty options{defaultErrorHandler=false;}: ;
>
> See:
> http://www.antlr.org/doc/options.html#defaultErrorHandler
>
> Sorry I didn't catch that...
>
> - Mark
>
Oddly enough I was looking at that option a few weeks ago...
What I ended up doing was:
optionalField: f:FIELD { ## = #[ABSENT,"absent empty tok"]; }
| { ## = #[ABSENT,"absent empty tok"]; }
Which works fine.
Thanks for your help!
Chris
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