anchor.diff:  
   
   //函数
  -function : CONSTANT LPAREN term (COMMA term)* RPAREN;
  +function : IDENTIFIER term;
   //简单项，缺_,#sup,#inf
   simpleterm : integer | CONSTANT | STRING | VAR;
   //元组
  -tuple : LPAREN ( | term ( | COMMA | (COMMA term)* )) RPAREN;
  +tuple : | COMMA | ( COMMA term )+ ;
   
   //范围枚举
  -interval : (integer | VAR) RANGE (integer | VAR);
  +//interval : (integer | VAR) RANGE (integer | VAR);
   //逐个枚举
  -pooling : LPAREN ((integer | VAR) (SEMICOLON (integer | VAR))* ) RPAREN;
  +pooling :  (SEMICOLON term)+;
   
   //项
   //term : VAR | CONSTANT | integer | arithmethic_expr | function | STRING;
  -term : simpleterm | function | tuple | arithmethic_expr | interval | pooling;
  +term : (simpleterm | function | arithmethic_expr | LPAREN term RPAREN) (tuple | pooling);
   
   //原子
   atom :
       CONSTANT |
  -    CONSTANT LPAREN term (COMMA term)* RPAREN;
  +    IDENTIFIER LPAREN term (COMMA term)* RPAREN;
   
   //文字
   literal : atom | MINUS atom | NAF_NOT literal | comparison_literal;
  
positive.code: soft_rule : (DECIMAL | integer ) CONDITION hard_rule;
  
  //
  meta_rule : META_OP (MINUS)? CONSTANT SLASH natural_number FULLSTOP;
  
  //ASP4QA程序
  lpmln_rule : (hard_rule | soft_rule | meta_rule)*;
negative.code: 
  //0
  ZERO : '0';
  //identifier
  IDENTIFIER : [_]*[a-z][a-zA-Z0-9_']*;
  //常量
  CONSTANT : IDENTIFIER | BOOL_CONSTANTS;
  //变量
  VAR : [_]*[A-Z][a-zA-Z0-9_']*;
  
  