code: public function handle(Context $context)
      {
          $ws = WS::getInstance();
          $ws->handle($context);
          $value = new Value();
          $value->handle($context);
          $ws->handle($context);
          
          if ($context->hasNext()) {
              $current = $context->current();
              throw $context->createException("Unexpected character('{$current}')");
          }
          
          $this->result = $value->getResult();
      }
docs: 指定された Context を解析します.
  
  @param Context $context
  @throws DecodeException