[antlr-interest] Newbie tree grammar question and rewrite rules

[Ted Villalba]

Hi,
 
I'm a little slow to pickup the concepts of the tree grammar, and looking
perhaps for some hints. I probably need to read through the chapter in the
ANTLR Reference a few more times, but in the meantime am hoping for some
guidance.
I have a fairly simple grammar which I include below, and one line with
which I am struggling is the following:
 
query :  (field | qid | LPAREN query RPAREN)  (BOOL_OP^ query  )*
      ;
 
It seems the simplest way to create a tree grammar is to simply cut and
paste the AST rewrite rules , so I considered rewriting the above, using an
AST rewrite rule. My question is, is there necessarily a rewrite rule that
can replace AST construction operators, and is this the generally
recommended approach - to have a rewrite rule for every alternative?
 
Thanks for your help,
Ted
 
P.S.
Here is the grammar I am working with:
 
grammar QueryParser;
 
options{
    k=1;
    output=AST;
    ASTLabelType=CommonTree;
}
 
// START:query
start      :           (query
{System.out.println($query.tree.toStringTree());} )+;
query :  (field | qid | LPAREN query RPAREN)  (BOOL_OP^ query  )*
      ;
 
field : tag '=' value -> ^('=' tag value)      ;
 
value : (term | LPAREN value RPAREN) (WOK_OP^ value )*       ;
 
term : WCHAR+
     | '"' WCHAR+ '"'
     ;
 
tag : WCHAR+ ;
 
qid : '#'DIGIT+ ;
 
 
BOOL_OP :       ' AND '|' OR '|' NOT ';
WOK_OP :       ' SAME ' | ' NEAR ';
DIGIT   :       ('0'..'9');
LPAREN  :       '(' ;
RPAREN  :       ')' ;
WCHAR   :       ('0'..'9'|'a'..'z'|'A'..'Z'|' ');
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