anchor.diff:      ;
   
   gccAttributeList
  -    :   gccAttribute (',' gccAttribute)*
  -    |   // empty
  +    :   gccAttribute? (',' gccAttribute?)*
       ;
   
   gccAttribute
       :   ~(',' | '(' | ')') // relaxed def for "identifier or reserved word"
           ('(' argumentExpressionList? ')')?
  -    |   // empty
       ;
   
   nestedParenthesesBlock
  
positive.code:     ;
  
  blockItemList
      :   blockItem
      |   blockItemList blockItem
      ;
  
  blockItem
  
negative.code: 
  fragment
  ExponentPart
      :   [eE] Sign? DigitSequence
      ;
  
  fragment
  Sign
      :   [+-]
      ;
  
  DigitSequence
  