[antlr-interest] Rewriting in non tree grammar

[Indhu Bharathi]

>$a.start.getTokenIndex() is better than relying on index probably.

Great! But how to do the same when I have a production like this:

a : b c b
  ;

Suppose I need to insert some text before the first 'b' as well as the
second 'b', I cannot write

{
	Input.insertBefore( $b.start.getTokenIndex(), "some text");
	Input.insertBefore( $b.start.getTokenIndex(), "some other text");
}

If 'b' is a lexer rule ('B'). then I can do 

a : t1=B c t2=B
{
	Input.insertBefore( t1, "some text");
	Input.insertBefore( t2, "some other text");
}
;

I tried doing the same thing for parser rule 'b' but it doesn't work. Any
idea how to get this working?


- Indhu


-----Original Message-----
From: Terence Parr [mailto:parrt at cs.usfca.edu] 
Sent: Friday, February 27, 2009 9:53 PM
To: indhu.b at s7software.com
Cc: antlr-interest
Subject: Re: [antlr-interest] Rewriting in non tree grammar


On Feb 27, 2009, at 12:43 AM, Indhu Bharathi wrote:

> Figured it out :-) Here is a sample grammar that does what is  
> required:
>
> grammar Test;
>
> @members {
> 	TokenRewriteStream input = (TokenRewriteStream) getTokenStream();
> }
>
> r
> @init {
> 	int pos;
> }
> 	:	a { pos = input.index(); } b
> 		{
> 			input.insertBefore(pos, "inserted");
> 		}
> 	;

$a.start.getTokenIndex() is better than relying on index probably.
Ter