original_string: public function is_set($field) {
          return (isset($this->data[$field]) || isset($this->extradata[$field]));
      }
code: public function is_set($field) {
          return (isset($this->data[$field]) || isset($this->extradata[$field]));
      }
code_tokens: public function is_set ( $ field ) { return ( isset ( $ this -> data [ $ field ] ) || isset ( $ this -> extradata [ $ field ] ) ) ; }
docstring: Checks if a field is set.
  
  @param string $field
  @return bool
docstring_tokens: Checks if a field is set .