anchor.diff:  //     = += -= *= %= **= <<= >>= >>>= &= |= ^=
   //     =>
   Punctuator
  -: OpenBrace     | OpenParen   | CloseParen      | OpenBracket       | CloseBracket
  +: (OpenBrace    | OpenParen   | CloseParen      | OpenBracket       | CloseBracket
   | Dot           | Spread      | SemiColon       | Comma
   | LessThan      | GreaterThan | LessThanEquals  | GreaterThanEquals
   | Equals        | NotEquals   | IdentityEquals  | IdentityNotEquals
  
positive.code: //    /
  //    /=
  DivPunctuator
  : Divide | DivideAssign
  ;
  
  // RightBracePunctuator::
  
negative.code: | Assign        | PlusAssign  | MinusAssign     | MultiplyAssign    | ModuloAssign      | PowerAssign
  | LeftShiftArithmeticAssign   | RightShiftArithmeticAssign          | RightShiftLogicalAssign
  | BitAndAssign  | BitOrAssign | BitXorAssign
  | FatArrow)
  ;
  
  Divide                     : '/';
  