WordPress useful classes function

/**
 * Include useful classes in body_class and post_class
 */
function dig_add_useful_classes($classes) {
	global $post;
	
	if( ! is_tag() ) {
		$classes[] = dig_get_post_type_class();
	}

	if( is_page() ) {
		global $post;
		$classes[] = 'page-' . $post->post_name;
	}

	return $classes;
}
add_filter('post_class', 'dig_add_useful_classes');
add_filter('body_class', 'dig_add_useful_classes');