Re: [YANG] default values

Balazs Lengyel writes:
>Why would the presence container come back automatically? There's today no text in the d
>raft, 
>that says presence containers are automatically removed or created.

"come back" in the virtual sense, so if the element isn't it the
document, it implicitly is there.  Isn't that what Martin meant by
"present by default"?

>Actually we failed to state what happens, if we later explicitly delete a leaf with a default 
>value. In my view if the user wants to delete it then it should go away; no value presen
>t any more.

If an element is deleted, the configuration should behave as if it never
were present, meaning it should revert to the default.  Otherwise there's
a difference in behavior between not having an statement in the config
and having it but deleting it.  This difference won't be reflected in
the "show" output, and reloading the config or rebooting the device will
give different behavior.

>One more thing I think is still missing from the draft, is whether must expressions cons
>ider 
>default values or not?

We discussed this at some point and decided that "must"s must
see defaults, but there needs to be a helper function to allow
one to detect unconfigured values.

    must "../mtu < 1500 or not(yang:is-set(../mtu))";

I don't think this is in the current spec.

Thanks,
 Phil

_______________________________________________
YANG mailing list
YANG@ietf.org
https://www1.ietf.org/mailman/listinfo/yang