[antlr-interest] Problem using += operator in actions

[Terence Parr]

Hi Martin,

This has been fixed.  Added a slew of unit tests.  It will magically  
appear in next build when I push.  I am *almost* satisfied that my  
new AST rewrite implementation correct.  Soon as I add yet more unit  
tests for this stuff I'll push.

Thanks for the impetus to fix this annoying bug.  It now binds +=  
tighter than + and * loops etc...

Ter
On Apr 17, 2007, at 6:00 AM, Martin Fowler wrote:

> This is another one of those problems I ended up solving myself but  
> I post here to help others.
>
> I wanted to collect together some words using the += operator. I  
> used a grammar line like this:
>
> item	: 'item'  w += WORD+ ';'
> 	{System.out.println("name is: " + $w);}
> 	 ;
>
> The problem was that $w ended up being null.
>
> My mistake was that the phrase w+=WORD needed to be contained in  
> parentheses before applying the +, like so:
>
> item	: 'item'  (w += WORD)+ ';'
> 	{System.out.println("name is: " + $w);}
> 	 ;
>
>
> -- 
> Martin Fowler
> http://martinfowler.com