def parse_ref_settings(s, l, t):
    """
    [delete: cascade]
    """
    result = {}
    if 'update' in t:
        result['on_update'] = t['update'][0]
    if 'delete' in t:
        result['on_delete'] = t['delete'][0]
    if 'comment' in t:
        result['comment'] = t['comment'][0]
    return result
