Hi Rob,
On Wed, 2019-06-12 at 09:25 +0000, Rob Wilton (rwilton) wrote:
> Hi Lada,
>
> OpenConfig have already introduced a module level extension statement to
> indicate that their pattern statements use POSIX regular expressions.
What I meant was rather something like
pattern-language "POSIX";
with the default being "XSD". It could possibly also include your proposal of
XSD regex subset (issue #21).
This could in fact be a good candidate for a critical extension.
>
> extension regexp-posix {
> description
> "This extension indicates that the regular expressions included
> within the YANG module specified are conformant with the POSIX
> regular expression format rather than the W3C standard that is
> specified by RFC6020 and RFC7950.";
> }
>
> Defined in
> https://github.com/openconfig/public/blob/master/release/models/openconfig-extensions.yang
>
> I don't think that this should become part of the YANG standard.
I suspect that developers of YANG tools are being pushed by users to include
support for this anyway, so I don't see much benefit from blocking it.
Lada
>
> Thanks,
> Rob
>
>
> > -----Original Message-----
> > From: netmod <[email protected]> On Behalf Of Ladislav Lhotka
> > Sent: 12 June 2019 09:02
> > To: NETMOD WG <[email protected]>
> > Subject: [netmod] regular expression flavours (again)
> >
> > Hi,
> >
> > I think it is very unfortunate that OpenConfig folks use POSIX regular
> > expressions instead of XSD. This of course causes confusion, see e.g. this
> > PR:
> >
> > https://github.com/CZ-NIC/yangson/pull/22
> >
> > Given the popularity of OpenConfig models, it seems to me that it would be
> > better if YANG somehow accomodates such (largely cosmetic) differences.
> >
> > One option would be that each YANG module declares the regex flavour used
> > in its patterns. Yes, it is a complication, but having separate forks of
> > YANG is much worse.
> >
> > ISO Schematron adopted a similar approach with "query language binding"
> > that can be declared with the schema element, for example
> >
> > <schema xmlns="http://purl.oclc.org/dsdl/schematron"; queryBinding="exslt">
> >
> > Any thoughts on this?
> >
> > Lada
> >
> > --
> > Ladislav Lhotka
> > Head, CZ.NIC Labs
> > PGP Key ID: 0xB8F92B08A9F76C67
> >
> > _______________________________________________
> > netmod mailing list
> > [email protected]
> > https://www.ietf.org/mailman/listinfo/netmod
--
Ladislav Lhotka
Head, CZ.NIC Labs
PGP Key ID: 0xB8F92B08A9F76C67
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