op_self_num
$$ = op_self_num(ITM_OP_ERROR_D, EINVAL);
$$ = op_self_num(ITM_OP_ERROR_D, $2->data.itm_exnum);
$$ = op_self_num(ITM_OP_DISCARD_D, 1);
$$ = op_self_num(ITM_OP_DISCARD_D, $2->data.itm_exnum);
itmc_obj_t *op_self_num(itm_op_type_t, itm_num_t);