[antlr-interest] Disambiguate following rules

[forumer at smartmobili.com]

Hi,

I have a grammar with the following rules and that is using backtrack 
option. Now when I remove backtrack
I have a problem with the var_decl rule :

Decision can match input such as "IDENTIFIER" using multiple 
alternatives: 1, 2


Any idea about how to fix this ?



variable_declaration
	: VAR variable_declaration_list
	|  empty_statement
	;

variable_declaration_list
	: var_decl ( ',' var_decl )*
	;


var_decl
	: identifier ( '=' expression )?
         | expression
	;

/***EXPR*************************/
expression
     : assignment_expression (',' assignment_expression )*
     ;

argument_expression_list
     : assignment_expression ( ',' assignment_expression )*
     ;

assignment_expression
     : conditional_expression ( assignment_operator 
assignment_expression )?
     ;

assignment_operator
     : '=' | '*=' | '/=' | '%=' | '+=' | '-=' | '<<=' | '>>=' | '&=' | 
'^=' | '|=' | '>>>='
     ;

constant_expression
     : conditional_expression
     ;

conditional_expression
     //: logical_or_expression  ( '?' logical_or_expression ':' 
logical_or_expression )?
     : logical_or_expression  ( '?' expression ':' expression )?
     ;

logical_or_expression
     : logical_and_expression ('||' logical_and_expression )*
     ;

logical_and_expression
     : inclusive_or_expression ('&&' inclusive_or_expression )*
     ;

inclusive_or_expression
     : exclusive_or_expression ('|' exclusive_or_expression )*
     ;

exclusive_or_expression
     : and_expression ('^' and_expression)* ;

and_expression
     : equality_expression ('&' equality_expression)*
     ;

equality_expression
     /* === and !== for javascript */
     : relational_expression (('!=' | '==' | '===' | '!==' ) 
relational_expression)*
     ;

relational_expression
     /* instanceof and in are for javascript */
     : shift_expression ( RELATION_OPERATOR shift_expression)*
     ;

RELATION_OPERATOR
     :  '<' | '>' | '<=' | '>=' | 'in' | 'instanceof'    // Don't 
tokenize these!
     ;

shift_expression
     : additive_expression (('<<' | '>>') additive_expression)*
     ;

additive_expression
     : multiplicative_expression (('+' | '-') 
multiplicative_expression)*
     ;

multiplicative_expression
     : unary_expression ( ('*' | REGEX_OR_DIVIDE | '%') unary_expression 
)*    /* no cast expression for objj */
     ;

unary_expression
     : postfix_expression
     | '++' unary_expression
     | '--' unary_expression
     | unary_operator unary_expression   /* no cast expression for objj 
*/
     ;

unary_operator
//    : '&' | '*' | '+' | '-' | '~' | '!'
     : '+' | '-' | '~' | '!'
     ;

postfix_expression
     : primary_expression
         ( '[' ']'
         | '[' expression ']'
         | '(' ')'
         | '(' argument_expression_list ')'
         | '.' identifier
         | '++'
         | '--'
         )*
     ;

primary_expression
     : TRUE | FALSE
     | 'defined' '(' expression ')'  /*  for prepocessing */
     | TYPEOF identifier                 /* javascript */
     | TYPEOF '(' identifier ')'         /* javascript */
     | '[' expression? ']'     /* objj array? DIES */
     | '[' expression ',' expression ( ',' expression )* ']'   /* objj 
array? DIES */
	| message_expression        /*   '[' receiver message_selector ']'  */
	| selector_expression
	| protocol_expression
	| encode_expression
     | '{' STRING_LITERAL ':' primary_expression ( ','  STRING_LITERAL 
':' primary_expression )* '}'  /* js obj array? */
     | '{' '}'                                                 /* js 
empty obj array? */
	| constant
     | identifier
     | VAR identifier
	| '(' expression ')'
     ;


identifier
     : a=IDENTIFIER { /*System.out.println ($a.text);*/ }
     ;

IDENTIFIER
	: ('_'|'A'..'Z'|'a'..'z')('_'|'A'..'Z'|'a'..'z'|'0'..'9')*
	;