code: private function term()
      {
          $result = $this->fact();
          while (($this->currentToken == '*') or
                 ($this->currentToken == '/')) {
              if ($this->currentToken == '*') {
                  $this->advance();
                  $result2 = $this->fact();
                  $result = $this->createTree('ptgMul', $result, $result2);
              } else {
                  $this->advance();
                  $result2 = $this->fact();
                  $result = $this->createTree('ptgDiv', $result, $result2);
              }
          }
  
          return $result;
      }
docs: It parses a term. It assumes the following rule:
  Term -> Fact [("*" | "/") Fact].
  
  @return mixed The parsed ptg'd tree on success