anchor.diff:      :   Identifier
       ;
   
  -declarator
  -    :   directDeclarator
  -    ;
  -
  -directDeclarator
  -    :   Identifier
  -    |   '(' declarator ')'
  -    |   directDeclarator '(' parameterTypeList ')'
  -    |   directDeclarator '(' identifierList? ')'
  -    |   Identifier ':' DigitSequence  // bit field
  -    ;
  -
  -parameterTypeList
  -    :   parameterList
  -    |   parameterList ',' '...'
  -    ;
  -
  -parameterList
  -    :   parameterDeclaration
  -    |   parameterList ',' parameterDeclaration
  -    ;
  -
  -parameterDeclaration
  -    :   declarationSpecifiers declarator
  -    ;
  +//declarator
  +//    :   directDeclarator
  +//    ;
  +//
  +//directDeclarator
  +//    :   Identifier
  +//    |   '(' declarator ')'
  +//    |   directDeclarator '(' parameterTypeList ')'
  +//    |   directDeclarator '(' identifierList? ')'
  +//    |   Identifier ':' DigitSequence  // bit field
  +//    ;
  +//
  +//parameterTypeList
  +//    :   parameterList
  +//    |   parameterList ',' '...'
  +//    ;
  +//
  +//parameterList
  +//    :   parameterDeclaration
  +//    |   parameterList ',' parameterDeclaration
  +//    ;
  +//
  +//parameterDeclaration
  +//    :   typeName Identifier
  +//    ;
   
   identifierList
       :   Identifier
  
positive.code: iterationStatement
      :   While '(' expression ')' statement
      |   Do statement While '(' expression ')' ';'
      |   For '(' forCondition ')' statement
      ;
  
  forCondition
  	:   forDeclaration ';' forExpression? ';' forExpression?
  	|   expression? ';' forExpression? ';' forExpression?
  	;
  
  forDeclaration
      :   declarationSpecifiers initDeclaratorList
  	| 	declarationSpecifiers
      ;
  
  forExpression
      :   assignmentExpression
  
negative.code:     ;
  
  constantExpression
      :   Constant
      ;
  
  //initDeclaratorList
  //    :   initDeclarator
  //    |   initDeclaratorList ',' initDeclarator
  //    ;
  //
  //initDeclarator
  //    :   declarator
  //    |   declarator '=' initializer
  //    ;
  
  enumSpecifier
      :   'enum' Identifier '{' enumeratorList '}'
  