anchor.diff:  grammar I0;
   
  -options 
  +options
   {
       language    = C;
       backtrack   = true;
  
positive.code:             $retval->JumpMode = I0Instruction::JI;
              $retval->Operands[0] = $target.retval;
          }
          | br_mode_compare ':' attr1 = attributes r2=br_relative op1 = operand ',' op2 = operand ',' op3 = immediate_operand
          {
              $retval->Attribute = $attr1.retval;
              $retval->JumpMode = $br_mode_compare.retval;
  
negative.code: LINE_COMMENT
      : '#' ~('\n'|'\r')* '\r'? '\n' {$channel=HIDDEN;}
      ;
  