Thanks a lot !. It works.
--- On Mon, 9/22/08, Jim Idle <[EMAIL PROTECTED]> wrote:
From: Jim Idle <[EMAIL PROTECTED]>
Subject: Re: [antlr-interest] Tree walker grammer help.
To: [EMAIL PROTECTED]
Cc: [EMAIL PROTECTED]
Date: Monday, September 22, 2008, 8:38 AM
On Mon, 2008-09-22 at 00:43 -0700, jack zhang wrote:
Oh yeah, you will have to put your multiple words under an imaginary so that
WORD WORD WORD AND WORD WORD WORD are not clashing.
use (w+=WORD) -> ^(WORDLIST $w+) in your parser and
expr
: .....
| ^(WORDLIST WORD+)
In your tree grammar
JIm
Sorry that I made a mistake in the previous post. So please ignore the previous
one.
I want to achieve following: (convert the input logic query to a standard
format)
(1) a AND b ==> (a and b)
(2) a OR b ==> (a or b)
(3) a OR b AND c ==> (a or (b and c))
(4) a b c ==> a b c (No change, since there is no logic involved)
(5) a b AND c ==> a (b and c)
By using the Antworks tool I know that the lexer and parser grammar works just
fine.
(It generate the correct AST tree).
But the strange thing is that my tree walker grammar doesn't work.
If I use the TreeWalker version 1(see attached code), test case 4 and 5 are
not working.
(4) a b c ==> a
(5) a b AND c ==> a
If I use the TreeWalker version 2(see attached code), test case 1,2,3 and 5 are
not working.
(1) a AND b ==> (a b and)
(2) a OR b ==> (a b or)
(3) a OR b AND c ==> ( a or ( b c and ))
(5) a b AND c ==> a
Also TreeWalker version 2 report warning:
-Decision can match input such as "WORD" using multiple alternatives: 1, 2
As a result, alternative(s) 2 were disabled for that input-
I know something is wrong with the matching of multiple WORD, But I just cannot
figure out.
The only difference with version 1 and verson 2 is the WORD rule.
Where am I wrong?
Thx !
----------------------Lexer and Parser ---------------------
grammar Query;
//=== Parser Option ===//
options {
output = AST;
k=*;
}
//=== Lexer ===//
LEFT_PAREN: '(';
NOT: 'NOT';
AND: 'AND';
OR: 'OR';
WORD: ('a'..'z' | 'A'..'Z' | '.' | ',' | '0'..'9')+ | '"'.+'"';
RIGHT_PAREN: ')';
WHITESPACE: (' ' | '\t' | '\r' | '\n') { $channel = HIDDEN; } ;
//=== Parser ===//
expr: orexpression*;
orexpression
: andexpression (OR^ andexpression)*
;
andexpression
: notexpression (AND^ notexpression)*
;
notexpression
: (NOT^)? atom
;
atom
: WORD
| LEFT_PAREN! expr RIGHT_PAREN!
;
----------------------Tree Walker Version 1 ---------------------
tree grammar QueryTree;
options {
output = AST;
ASTLabelType = CommonTree;
tokenVocab=Query;
}
expr returns [String value=""]
: ^(AND a=expr b=expr) {
$value = "(" + $a.value + " and " + $b.value + ")";
}
| ^(OR a=expr b=expr) {
$value = "(" + $a.value + " or " + $b.value+ ")";
}
| ^(NOT a=expr) {
$value = "(not " + $a.value +")";
}
| ( WORD { $value = $WORD.text; }) ;
----------------------Tree Walker Version 2 ---------------------
tree grammar QueryTree;
options {
output = AST;
ASTLabelType = CommonTree;
tokenVocab=Query;
}
expr returns [String value=""]
: ^(AND a=expr b=expr) {
$value = "(" + $a.value + " and " + $b.value + ")";
}
| ^(OR a=expr b=expr) {
$value = "(" + $a.value + " or " + $b.value+ ")";
}
| ^(NOT a=expr) {
$value = "(not " + $a.value +")";
}
| ( WORD { $value += " " + $WORD.text; })+ ;
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