List child page. Function to add in function.php

child-pages.php

/*
<?php while(mytheme_page_children()): ?>

  <?php echo page_title(); ?>

<?php endwhile; ?>
*/

function mytheme_page_children() {
	if( ! Registry::has('page_original')) {
		Registry::set('page_original', $original);
	}

	if( ! $pages = Registry::get('page_children')) {
		$query = Page::where('status', '=', 'published')->where('parent', '=', page_id())->get();

		Registry::set('page_children', $pages = new Items($query->get()));
	}

	if($result = $pages->valid()) {
		Registry::set('page', $pages->current());

		$pages->next();
	}
	else {
		$pages->rewind();

		Registry::set('page', Registry::get('page_original'));

		Registry::set('page_original', false);
	}

	return $result;
}