> On 05 Oct 2015, at 17:35, Balazs Lengyel <balazs.leng...@ericsson.com> wrote:
>
> Hello,
> What do the mandatory statements mean in the following model ?
>
> choice scen8 { // Embedded choices with multiple mandatory cases;
> invalid scenario
> case A {
> choice subChoiceA {
> mandatory true;
> case A {
> leaf scen8-num1 { type uint8; }
> }
> case B {
> leaf scen8-num2 { type uint8; }
> }
> }
> }
> case B {
> choice subChoiceB {
> mandatory true;
> case A {
> leaf scen8-num1 { type uint8; }
> }
> case B {
> leaf scen8-num2 { type uint8; }
> }
> }
> }
> }
>
> Answers:
> A1) They mean nothing because the case around subChoiceA/B might not exist,
> in which case its underlying statements are not valid.
> A2) They mean that one case from both subChoiceA AND subchoiceB must exist
> leading to two cases in choice scen8 which is not allowed, hence this is an
> invalid model?
In the first place, it should be an error because of colliding names - all the
leaves defined in sub-cases have the same parent. However, pyang doesn't flag
it as an error.
>
> Generally I find choices embedded in choices to be so complicated that IMHO
> they SHOULD be immediately prohibited. If you think about all the variants of
> embedded choices with mandatory and default placed on some or a bunch of
> them, even understanding what they mean becomes a headache. BAD !!!! In the
> beginning YANG was about easy-understanding. However these combinations are
> unclear even after repeatedly reading the RFC :-(
Yes, it is quite complicated. Normally, such embedded choices shouldn't be
needed but they can happen if, e.g. the internal choices are defined in
groupings.
> As the very least we SHOULD prohibit mandatory/default on the inside choice.
I think it would be better to ignore them (and tools may issue a warning).
Lada
>
> regards Balazs
>
> --
> Balazs Lengyel Ericsson Hungary Ltd.
> Senior Specialist
> ECN: 831 7320
> Mobile: +36-70-330-7909 email: balazs.leng...@ericsson.com
>
> _______________________________________________
> netmod mailing list
> netmod@ietf.org
> https://www.ietf.org/mailman/listinfo/netmod
--
Ladislav Lhotka, CZ.NIC Labs
PGP Key ID: E74E8C0C
_______________________________________________
netmod mailing list
netmod@ietf.org
https://www.ietf.org/mailman/listinfo/netmod
