code: function getImportant(scanner) {
      scanner.eat(EXCLAMATIONMARK);
      scanner.skipSC();
  
      var important = scanner.consume(IDENTIFIER);
  
      // store original value in case it differ from `important`
      // for better original source restoring and hacks like `!ie` support
      return important === 'important' ? true : important;
  }
docs: ! ws* important