comment.module

/**
 * Theme comment flat collapsed view.
 *
 * @param $comment
 *   The comment to be themed.
 * @param $node
 *   The comment node.
 * @ingroup themeable
 */
function theme_comment_flat_collapsed($comment, $node) {
  return theme('comment_view', $comment, $node, '', 0);
}

/**
 * Theme comment flat expanded view.
 *
 * @param $comment
 *   The comment to be themed.
 * @param $node
 *   The comment node.
 * @ingroup themeable
 */
function theme_comment_flat_expanded($comment, $node) {
  $links = module_invoke_all('link', 'comment', $comment, 0);
  drupal_alter('comment_links', $links);
  return theme('comment_view', $comment, $node, $links));
}

/**
 * Theme comment thread collapsed view.
 *
 * @param $comment
 *   The comment to be themed.
 * @param $node
 *   The comment node.
 * @ingroup themeable
 */
function theme_comment_thread_collapsed($comment, $node) {
  return theme('comment_view', $comment, $node, '', 0);
}

/**
 * Theme comment thread expanded view.
 *
 * @param $comment
 *   The comment to be themed.
 * @param $node
 *   The comment node.
 * @ingroup themeable
 */
function theme_comment_thread_expanded($comment, $node) {
  $links = module_invoke_all('link', 'comment', $comment, 0);
  drupal_alter('comment_links', $links);
  return theme('comment_view', $comment, $node, $links));
}