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