anchor.diff:      | '\\' '\r'? '\n'
       | DecimalEscape
       | HexEscape
  +    | UtfEscape
       ;
       
   fragment
  
positive.code: fragment
  HexEscape
      : '\\' 'x' HexDigit HexDigit
      ;
  
  fragment
  
negative.code: 	: '+' | '-';
  
  operatorMulDivMod
  	: '*' | '/' | '%' | '//';
  
  operatorBitwise
  	: '&' | '|' | '~' | '<<' | '>>';
  
  operatorUnary
      : 'not' | '#' | '-' | '~';
  
  operatorPower
      : '^';
  