> On 18 Oct 2015, at 04:49, Randy Presuhn <randy_pres...@mindspring.com> wrote: > > Hi - > >> From: Andy Bierman >> Sent: Oct 17, 2015 10:42 AM > ... >> Subject: Re: [netmod] 6020bis extensions > ... > > Andy Proposed: > >> If a YANG parser does not support a particular extension, which >> appears in a YANG module as an unknown-statement (see Section 14), >> the entire unknown-statement MAY be ignored by the parser. Note that >> this only applies to a generic YANG parser. A tool which is required >> to implement the particular extension MUST NOT ignore such an >> unknown-statement. > > I'd suggest a slightly different wording: > > The processing of extensions depends on whether support for those > extensions is claimed for a given YANG parser or the tool set in > which it is embedded. An unsupported extension, appearing in a > YANG module as an unknown-statement (see Section 14) MAY be > ignored in its entirety. Any supported extension MUST be processed > in accordance with the specification governing that extension.
I like this text. Do we also want to restrict semantics of extensions? If an extension changes YANG validity or datastore semantics, then a tool or protocol implementation that doesn't support that extension may not be able to correctly interpret instance data, or may outright break down. In order to be able to support annotations in instance data, it is IMO necessary to define the concept of annotations directly in the YANG spec. A similar approach as for YANG extensions could perhaps be used for annotations: The processing of annotations depends on whether support for those annotations is claimed for a given protocol or tool set. An unsupported annotation appearing in instance data or protocol messages MAY be ignored. Any supported annotation MUST be processed in accordance with the specification governing that annotation. Lada > > Randy > > _______________________________________________ > 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
