code: private function handleFractionPart(Context $context)
      {
          if ($context->current() !== ".") {
              return;
          }
          
          $this->result .= ".";
          $this->isFloat = true;
          $context->next();
          $this->handleFirstDigit($context);
          $this->handleDigitSequence($context);
      }
docs: frac = decimal-point 1*DIGIT
  
  @param Context $context