anchor.diff:      :   Constant
       ;
   
  -//initDeclaratorList
  -//    :   initDeclarator
  -//    |   initDeclaratorList ',' initDeclarator
  -//    ;
  -//
  -//initDeclarator
  -//    :   declarator
  -//    |   declarator '=' initializer
  -//    ;
  -
  -enumSpecifier
  -    :   'enum' Identifier '{' enumeratorList '}'
  -    |   'enum' Identifier '{' enumeratorList ',' '}'
  -    ;
  -
  -enumeratorList
  -    :   enumerator
  -    |   enumeratorList ',' enumerator
  -    ;
  -
  -enumerator
  -    :   enumerationConstant
  -    |   enumerationConstant '=' constantExpression
  -    ;
  -
  -enumerationConstant
  -    :   Identifier
  -    ;
  -
  -//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
  -    |   identifierList ',' Identifier
  -    ;
  -
   typeName
       :   Identifier
  -    ;
  -
  -initializer
  -    :   assignmentExpression
  -    |   '{' initializerList '}'
  -    |   '{' initializerList ',' '}'
  -    ;
  -
  -initializerList
  -    :   designation? initializer
  -    |   initializerList ',' designation? initializer
  -    ;
  -
  -designation
  -    :   designatorList '='
  -    ;
  -
  -designatorList
  -    :   designator
  -    |   designatorList designator
  -    ;
  -
  -designator
  -    :   '[' constantExpression ']'
  -    |   '.' Identifier
       ;
   
   statement
  
positive.code:     |   postfixExpression '->' Identifier
      |   postfixExpression '++'
      |   postfixExpression '--'
      |   '(' typeName ')' '{' initializerList '}'
      |   '(' typeName ')' '{' initializerList ',' '}'
      ;
  
  argumentExpressionList
  
negative.code: IdentifierNondigit
      :   Nondigit
      |   UniversalCharacterName
      ;
  
  fragment
  