original_string: public function next()
      {
          $operation   = $this->operation;
          $this->value = $operation($this->value);
          $this->elementsGenerated++;
      }
code: public function next()
      {
          $operation   = $this->operation;
          $this->value = $operation($this->value);
          $this->elementsGenerated++;
      }
code_tokens: public function next ( ) { $ operation = $ this -> operation ; $ this -> value = $ operation ( $ this -> value ) ; $ this -> elementsGenerated ++ ; }
docstring: generates next value
docstring_tokens: generates next value