Hi, I am strongly against adding more features to YANG 1.1 at this time. The deadline for new features has long passed.
Andy On Fri, Jan 22, 2016 at 12:27 AM, Balazs Lengyel < balazs.leng...@ericsson.com> wrote: > Hello, > I agree we don't need to change the encoding, but we need to define how > that encoding is visible/available when evaluating Xpath expressions. Today > the draft says: > - instance-identifier does not have a canonical format > - XPath uses the canonical format > The two together make it impossible to use it in Xpath, even though there > are people that would like to do that. > - Martin mentioned a proprietary extension > - we would like it. > > So I would propose to > ---- change to 9.1 > > Old: In particular, any XPath expression evaluations are done using the > canonical form. > > New: In particular, whenever a canonical form exists, any XPath > expression evaluations are done using the canonical form. > > --- add to 9.13.2 > > For instance-identifiers XPath expression evaluations are done using the > lexical form. > > > regards Balazs > > > On 2016-01-21 18:53, Andy Bierman wrote: > > Hi, > > There is no need to change the XML encoding or YANG encoding > of an instance-identifier. The prefixes are completely different > in each. Prefixes clashes do happen, especially since > there is no expectation that they are unique. They are short strings > with no naming conventions at all. E.g., I have seen "if" for > interfaces in multiple modules. > > Andy > > > On Thu, Jan 21, 2016 at 8:51 AM, Balazs Lengyel < > <balazs.leng...@ericsson.com>balazs.leng...@ericsson.com> wrote: > >> Hello Martin, >> If the RFC would define that in XPath expressions an instance identifier >> MUST be evaluated to a string that complies to the lexical format, using >> the rematch function, we could do everything we need. In real life prefix >> clashes are a rare problem. >> regards Balazs >> >> On 2016-01-21 16:17, Martin Bjorklund wrote: >> >>> Balazs Lengyel <balazs.leng...@ericsson.com> wrote: >>> >>>> Hello, >>>> We have some instance identifiers in our model but we want to >>>> contrain what they can point at. What is the best method for that? >>>> >>> Unfortunately, there is no standard way of doing this. (There are >>> vendor extensions available...) >>> >>> [...] >>> >>> Some issues: >>>> - instance-identifiers don't have a canonical format, so what is >>>> their value in an XPath expression? >>>> >>> This is not defined. >>> >>> - I didn't find a way to evaluate a regexp in XPath 1.0. Is there a way? >>>> >>> In YANG 1.1, there is a function re-match() for this purpose. For >>> your use case, it *may* work to match just the local names of all >>> nodes, i.e., using wildcards for the prefixes. It is not a generic >>> solution though. >>> >>> - if I have all the needed namespace prefixes in imports, can I just >>>> use them? >>>> >>> No, these prefixes are local to the module that is doing the import, >>> and they may or may not match the prefixes used by the implementation >>> when it construct the instance-identifier value. >>> >>> >>> >>> /martin >>> >>> >> -- >> Balazs Lengyel Ericsson Hungary Ltd. >> Senior Specialist >> ECN: 831 7320 >> Mobile: +36-70-330-7909 email: <balazs.leng...@ericsson.com> >> balazs.leng...@ericsson.com >> >> _______________________________________________ >> netmod mailing list >> netmod@ietf.org >> https://www.ietf.org/mailman/listinfo/netmod >> > > > -- > Balazs Lengyel Ericsson Hungary Ltd. > Senior Specialist > ECN: 831 7320 > Mobile: +36-70-330-7909 email: balazs.leng...@ericsson.com > >
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