[antlr-interest] Rule automation

[John B. Brodie]

Greetings!

On Wed, 2009-09-09 at 10:45 +0200, Martin Potier wrote:
> I've got something on my mind that the Definitive ANTLR Reference
> couldn't solve (yet, I'm not tottally through it).
> Is there a way with ANTLR v3 to automate some rule ?
> 
> Id est, while building a small wiki language I wrote this kind of rule :
> text
>     : (PURETEXT ( inlinenv | PURETEXT )*)
>     | (inlinenv (PURETEXT | inlinenv)*)
>     ;
> 
> In fact, I use the same sort of rule every time  I introduce text in a
> inlinenv.
> 
> I'd like to know if there's a way to create a generic rule like the
> following :
> generic altern ((ARG1, ARG2))
>     : (ARG1 (ARG2 | ARG1)*)
>     | (ARG2 (ARG1 | ARG2)*)
>     ;
> 
> And then reuse it, like an operator ?
> 
> 

As earlier replies have stated ANTLR does not do that (at the moment
anyway).

But I just wanted to point out to you that any rule of the form:

any_rule
    : ( arg1 ( arg2 | arg1 )* )
    | ( arg2 ( arg1 | arg2 )* )
    ;

is the same as:

any_rule : ( arg1 | arg2 )+ ;

might save you some keyboarding in your .g file....

Not much value added, but hope this helps.
   -jbb