function repeater_function() {

    $output = '<ul>';

    $rows = get_field( 'repeater_field' );

    foreach ($rows as $row )

        $output .= '<li>' . $row['title'] . '</li>';

    }

    $output .= '</ul>';

    return $output;

}

add_shortcode( 'my_repeater', 'repeater_function' );