code: public function next()
      {
          if (!isset($this->tokens[++$this->current])) {
              throw new Twig_Error_Syntax('Unexpected end of template.', $this->tokens[$this->current - 1]->getLine(), $this->source);
          }
  
          return $this->tokens[$this->current - 1];
      }
docs: Sets the pointer to the next token and returns the old one.
  
  @return Twig_Token