docs: def p_jointype(self,t):
      """jointype : kw_join
                  | kw_inner kw_join
                  | outerjoin kw_outer kw_join
                  | outerjoin kw_join
      """
      if len(t) <= 2 or t[1] == 'inner': t[0] = JoinTypeX(None, False, None)
      else: t[0] = JoinTypeX(t[1], True, None)