term_relation un-todo-ed?

Only mention of term_relation is a lil comment with "TODO".

Based on the lack of any issue about it, generally guess no one desired this before (only one result for term_relation, and that was a list of someone's tables).

Anyhow I made a quick thing for being able to get term list based on term_relation argument
Will make a patch if this is desired, but personally dislike how I did it, and not much desire in general it seems for it, etc... so don't see it being used (stuffed in a personal module At the moment). But might as well post it

function multivocabrelatedterm_views_data() {
  $data = array();
  $data['term_data']['term_relationship'] = array(
    'group' => t('Taxonomy'),
    'title' => t('Term relation'),
    'help' => t('Related term.'),
    'real field' => 'tid',
    'argument' => array(
      'handler' => 'views_handler_argument_term_data_term_relationship',
    ),
  );
  return $data;
}

function multivocabrelatedterm_views_handlers() {
  return array(
    'info' => array(
      'path' => drupal_get_path('module', 'multivocabrelatedterm'),
    ),
    'handlers' => array(
      'views_handler_argument_term_data_term_relationship' => array(
        'parent' => 'views_handler_argument',
      ),
    ),
  );
}

and the handler (or at github http://github.com/hefox/vocabulary/blob/master/multivocabrelatedterm/vie...)

/**
 */
class views_handler_argument_term_data_term_relationship extends views_handler_argument {
  function query() {
    $this->ensure_my_table();
    $args = array($this->argument,$this->argument);
    $this->query->add_where(0, "$this->table_alias.tid in (SELECT tid2 from {term_relation} where tid1 = %d) OR $this->table_alias.tid in (SELECT tid1 from {term_relation} where tid2 = %d)", $args); // Ewwww 
  }

  function title() {
    $term = taxonomy_get_term($this->argument);
    if (!empty($term)) {
      return check_plain($term->name);
    }
    // TODO review text
    return t('No name');
  }
}