On Wed, Apr 12, 2023 at 10:04 AM Jeffrey Haas <jh...@pfrc.org> wrote:
> Tom, > > > > On Apr 12, 2023, at 12:44 PM, tom petch <ie...@btconnect.com> wrote: > >> The reason to disconsider it is that within the same leaf, the value > "changes meaning" once you end up with the new identity for the value when > it's assigned and then end up with an orphaned identity. Implementations > looking at that bit for that leaf now need to "know" they are equivalent. > For the moment, the only hint that YANG can provide about this equivalency > is in the description. > >> > >> At least within the bits construct, bit number assignment is always > crystal clear. > >> > > <tp> > > > > That caught my eye and I am not sure I understand, As the I-D says, a > bit is identified by its name and the canonical form is a list of > space-separated names, bit number assignment I do not see except as a > local convention which I would not call crystal clear. > > With bits, if bit position 3 is "foo", you always know that foo is > bit-position 3. > > With identities, identity foo from base bar is simply "foo" and if it has > anything to do with bit-position 3, it's listed by description. > If you define foo2 and it's semantically the same as bit-position 3, an > implementation could render "foo foo2", "foo", or "foo2". The underlying > type doesn't provide machinery that enforces what you do. > > Somewhat maddening if you're trying to see what bits on the wire are. If > you're driven to "just give me the hexdump", we've lost the ease of use > game. > I unclear on the "ease of use" gained by using YANG bits to define bit positions. IMO is would be much easier to use a protocol-specific leaf if you want to debug a specific protocol. An operational leaf like "raw-foo-field" is sufficient and easy to use. The only semantics seems to be the bit position, which is already standardized and can be represented many ways (e.g. hex-string, binary, uint32). > -- Jeff > Andy > > _______________________________________________ > netmod mailing list > netmod@ietf.org > https://www.ietf.org/mailman/listinfo/netmod >
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