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

[Ladislav Lhotka <[e-mail]>]

Andy Bierman <[e-mail]> writes:
>
> 5.12.  The "union" Type
>
>    Leafs of type union MUST be encoded using the rules associated with
>    one of the types listed.
>
> C10) This does not really work because so many YANG types use
> the same CBOR major encoding

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.

>
>    type union {
>       type int32;
>       type enumeration {
>         enum A { value -5; }
>         enum B { value 3; }
>       }
>       type bits {
>         bit X { position 1; }
>         bit Y { position 3; }
>       }
>       type decimal64 {
>         fraction-digits 2;
>       }
>    }
>
> How do I know if '3' is for int32, enum B or bit Y?

If it's major type 0 or 1, it will be int32 in this case because int32 is the
first applicable member type.

> How do I know 103 is really decimal64 "1.03" and not
> an int32 "103"?

If it's major type 0 or 1, then it will be again int32. However, 2147483648
would become 21474836.48 because that integer doesn't fit the int32 range.

Lada

-- 
Ladislav Lhotka, CZ.NIC Labs
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