Re: [core] Comments on draft-ietf-core-yang-cbor-00

[Juergen Schoenwaelder <[e-mail]>]

On Sat, May 21, 2016 at 10:30:58AM +0200, Carsten Bormann wrote:
> Ladislav Lhotka wrote:
> > The receiving side will resolve the union type by the first union member
> > type that matches the CBOR-encoded value. It's the same as in JSON encoding.
> 
> Or, at least, similar -- we are not always making the same serialization
> decisions.
> 
> The weird aspect of this part of YANG is that the actual validity (and
> specific semantics and thus usefulness) of a union in the YANG module
> depends on the specifics of the serialization below.

YANG's native serialization of values are untyped strings.

> More frankly: Tying the semantics of a modeling language to one specific
> serialization mechanism is an utterly broken design.

Not necessarily. It may start to look broken once you have
serializations that are typed and for some reasons people think the
type information should impact how YANG works (that assumes values
serialized as untyped strings). Note that type rules differ for
different serializations so you actually have no chance to get away
without any weird corner cases.

> I'm not sure that it can be fixed, though, so we'll likely have to work
> around this breakage.

I disagree that YANG is broken.

/js

-- 
Juergen Schoenwaelder           Jacobs University Bremen gGmbH
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