[antlr-interest] Problem using += operator in actions
Martin Fowler
fowler at acm.org
Tue Apr 17 06:00:58 PDT 2007
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
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