Re: [netmod] regular expression flavours (again)
Ladislav Lhotka <lhotka@nic.cz> Wed, 12 June 2019 09:39 UTC
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From: Ladislav Lhotka <lhotka@nic.cz>
To: "Rob Wilton (rwilton)" <rwilton@cisco.com>, NETMOD WG <netmod@ietf.org>
Date: Wed, 12 Jun 2019 11:39:37 +0200
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Subject: Re: [netmod] regular expression flavours (again)
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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 <netmod-bounces@ietf.org> On Behalf Of Ladislav Lhotka > > Sent: 12 June 2019 09:02 > > To: NETMOD WG <netmod@ietf.org> > > 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 > > netmod@ietf.org > > https://www.ietf.org/mailman/listinfo/netmod -- Ladislav Lhotka Head, CZ.NIC Labs PGP Key ID: 0xB8F92B08A9F76C67
- Re: [netmod] regular expression flavours (again) Rob Wilton (rwilton)
- [netmod] regular expression flavours (again) Ladislav Lhotka
- Re: [netmod] regular expression flavours (again) Juergen Schoenwaelder
- Re: [netmod] regular expression flavours (again) Ladislav Lhotka
- Re: [netmod] regular expression flavours (again) Rob Wilton (rwilton)
- Re: [netmod] regular expression flavours (again) Ladislav Lhotka
- Re: [netmod] regular expression flavours (again) Martin Bjorklund
- Re: [netmod] regular expression flavours (again) Robert Varga
- Re: [netmod] regular expression flavours (again) Robert Varga
- Re: [netmod] regular expression flavours (again) Juergen Schoenwaelder
- Re: [netmod] regular expression flavours (again) Ladislav Lhotka
- Re: [netmod] regular expression flavours (again) Carsten Bormann
- Re: [netmod] regular expression flavours (again) Carsten Bormann
- Re: [netmod] regular expression flavours (again) Rob Wilton (rwilton)
- Re: [netmod] regular expression flavours (again) Rob Wilton (rwilton)
- Re: [netmod] regular expression flavours (again) Carsten Bormann
- Re: [netmod] regular expression flavours (again) Robert Varga