foreach ($terms as $term) :
	if ($term->parent == 0) {
		$out .= ($current == $term->slug) ?
			'<li><a href="' . get_term_link($term->slug, 'catalog') . '" class="current"><span><!-- --></span>' . $term->name . '</a></li>' :
			'<li><a href="' . get_term_link($term->slug, 'catalog') . '"><span><!-- --></span>' . $term->name . '</a></li>';
	}
endforeach;