Why does 'author' also search in editor?

You would have to add a "where" limit to the query in the "author" section...

        case 'author':
          $bcc++;
          $term = explode("?",array_shift($arg_list));

          if (is_numeric($term[0])){
            $joins[] = "inner join {biblio_contributor} as bc". $bcc ." on n.vid = bc". $bcc .".vid";
            $cids = db_query('SELECT cid FROM {biblio_contributor_data}
                              WHERE cid = %d OR aka = (SELECT aka FROM {biblio_contributor_data} WHERE cid = %d)'
                              ,$term[0], $term[0]);
            while ($cid = db_fetch_object($cids) ){
              $wr .= empty($wr)?'':' OR ';
              $wr .= "bc". $bcc .".cid = $cid->cid ";
            }
            $where[] = (!empty($wr)) ? $wr : "bc". $bcc .".cid = -1 ";
            $where[] = 'bc.auth_category=1';
          }else{
            $where[] = " bcd". $bcc .'.name '. $match_op .' "[[:<:]]%s[[:>:]]" ';
            $joins[] = " JOIN {biblio_contributor} as bc". $bcc ." on b.vid = bc". $bcc .".vid ";

Note the new line "$where[] = 'bc.auth_category=1';" just before the {else}

Ron.

Right you are, I hadn't actually "tested" the code I posted :-(

WRT an optional setting, that's probably a good idea, although you are the first to raise it.

Ron.

This problem still exists in the version for drupal 7: when looking for publications of a certain author, I do not want the publications of which that person was the editor.

I found a comment line:
// $query->condition('bc.auth_category', 1);
but uncommenting this, does not seem to change anything. How can I only see the publications that person is really the author of, and not the editor?

I'm revisiting all that filtering code (as there are some other issues as well, #1399866: Filtering publications always returns zero results) so I'll look at this at the same time.

This version is no longer maintained. If this issue is still relevant to the Drupal 7 version, please re-open and provide details.