Provide context per field (for taxonomy, at least)

I have some custom code which works along the following lines:

/**
 * Implements of hook_node_view().
 */
function MODULE_node_view($node, $view_mode, $langcode) {
  if ($node->type == 'CONTENT_TYPE' && $view_mode == 'full') {
    $tids = array();
    if ($items = field_get_items('node', $node, 'field_FIELD')) {
      foreach ($items as $item) {
        $tids[] = $item['tid'];
      }
    }
    context_set('field', 'field_FIELD-or', join('+', $tids));
    context_set('field', 'field_FIELD-and', join(',', $tids));
  }
}

It would be good to generalize this for all taxonomy term reference fields in D7, or perhaps even extend it to more field types. For now I'm just putting this out there in case it helps anyone else who needs context for a specific vocabulary rather than all terms in one context.