antlr3 - ANTLR v3 grammar for boolean/conditional expression -

i'm taking first stab @ creating grammar expressions like:

(foo = bar or (bar = "bar" , baz = 45.43)) , test = true 

my grammar far looks like:

grammar filter;  tokens {     true = 'true';     false = 'false';     , = 'and';     or = 'or';     lt = '<';     gt = '>';     eq = '=';     neq = '!=';     pathsep = '/';     lbrack = '[';     rbrack = ']';     lparen = '(';     rparen = ')'; }  expression : or_expression eof;  or_expression : and_expression (or or_expression)*;  and_expression : term (and term)*;  term : atom ( operator atom)? | lparen expression rparen;  atom : id | int | float | string | true | false;  operator : lt | gt | eq | neq;  int : '0'..'9'+; float : ('0'..'9')+ '.' ('0'..'9')*; string : '"' ('a'..'z'|'a'..'z'|'_'|' ')* '"'; id : ('a'..'z'|'a'..'z'|'_') ('a'..'z'|'a'..'z'|'0'..'9'|'_')*; 

but in antlrworks 1.4.3, parse tree:

but life of me can't figure out wrong grammar. token missing here?

many in advance.

edit: clarify atom ( operator atom)? alternative in atom production, should perhaps mention atoms should able free-standing without comparison atom. e.g. a or b valid expression.

i'm answering own question here. found 2 problems grammar. first easy spot; had put eof @ end of top-level rule:

expression : or_expression eof; 

the eof missing token. solution remove eof expression rule, , instead introduce rule above it:

filter: expression eof; 

the second problem or_expression rule should be:

or_expression : and_expression (or and_expression)*; 

and not

or_expression : and_expression (or or_expression)*; 

the full corrected grammar is:

grammar filter;  tokens {     true = 'true';     false = 'false';     , = 'and';     or = 'or';     lt = '<';     gt = '>';     eq = '=';     neq = '!=';     pathsep = '/';     lbrack = '[';     rbrack = ']';     lparen = '(';     rparen = ')'; }  filter: expression eof;  expression : or_expression;  or_expression : and_expression (or and_expression)*;  and_expression : term (and term)*;  term : atom (operator atom)? | lparen expression rparen;  atom : id | int | float | string | true | false;  operator : lt | gt | eq | neq;  int : '0'..'9'+; float : ('0'..'9')+ '.' ('0'..'9')*; string : '"' ('a'..'z'|'a'..'z'|'_'|' ')* '"'; id : ('a'..'z'|'a'..'z'|'_') ('a'..'z'|'a'..'z'|'0'..'9'|'_')*; 

and resulting parse tree is: