original_string: public function filter_by_author_non_letter($firstnamefirst = false) {
          $field = self::get_fullname_field($firstnamefirst);
          $this->filter_by_non_letter($field);
      }
code: public function filter_by_author_non_letter($firstnamefirst = false) {
          $field = self::get_fullname_field($firstnamefirst);
          $this->filter_by_non_letter($field);
      }
code_tokens: public function filter_by_author_non_letter ( $ firstnamefirst = false ) { $ field = self :: get_fullname_field ( $ firstnamefirst ) ; $ this -> filter_by_non_letter ( $ field ) ; }
docstring: Filter the author by special characters.
  
  @param bool $firstnamefirst Whether or not the firstname is first in the author's name.
docstring_tokens: Filter the author by special characters .