Re: analysis of YANG vs. RELAX NG
Juergen Schoenwaelder <j.schoenwaelder@jacobs-university.de> Mon, 03 December 2007 14:09 UTC
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Date: Mon, 03 Dec 2007 15:08:46 +0100
From: Juergen Schoenwaelder <j.schoenwaelder@jacobs-university.de>
To: Ladislav Lhotka <lhotka@cesnet.cz>
Subject: Re: analysis of YANG vs. RELAX NG
Message-ID: <20071203140846.GB17536@elstar.local>
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On Mon, Dec 03, 2007 at 02:56:02PM +0100, Ladislav Lhotka wrote: > Tim Bray p????e v Ne 02. 12. 2007 v 12:42 -0800: > > I've been staying off this thread because I don't understand what a > > NETCONF is or what you'd do with one. But Julian's point is massively > > important. If you're going to design your own modeling language, you > > need to spend a *lot* of time thinking about the extensibility model. > > It's really easy to get wrong. -Tim > > Indeed. An extensibility problem in YANG is IMO the leaf statement. It > is encoded as an XML element but the fact that it is declared as leaf > effectively makes it into an XML attribute: It is impossible to extend > it (e.g., add a qualifying subelement) without changing the leaf into > container. In a RELAX NG schema, if properly designed, such an extension > wouldn't have to touch the parent schema. Leafs carry data and we strongly dislike mixed contents in NETCONF. So this is actually a YANG feature and not a bug. > Another problem might be the default statement in leaves (or it is > proper to say leafs here?:-) or typedefs. What if a standard data model > defines an item, say a hello timer, with such a default, but an > implementation wants to use another value for the default? Should it > come up with another schema? No. There can only be one standard default. If you are thinking about reusable groupings, then defaults can actually be changed wherever you apply a grouping as far as I know. /js -- Juergen Schoenwaelder Jacobs University Bremen gGmbH Phone: +49 421 200 3587 Campus Ring 1, 28759 Bremen, Germany Fax: +49 421 200 3103 <http://www.jacobs-university.de/>
- analysis of YANG vs. RELAX NG Rohan Mahy
- Re: analysis of YANG vs. RELAX NG Martin Bjorklund
- Re: analysis of YANG vs. RELAX NG Leif Johansson
- Re: analysis of YANG vs. RELAX NG Juergen Schoenwaelder
- Re: analysis of YANG vs. RELAX NG Juergen Schoenwaelder
- Re: analysis of YANG vs. RELAX NG Paul Hoffman
- RE: analysis of YANG vs. RELAX NG Natale, Bob
- Re: analysis of YANG vs. RELAX NG Lisa Dusseault
- Re: analysis of YANG vs. RELAX NG Rohan Mahy
- Re: analysis of YANG vs. RELAX NG Juergen Schoenwaelder
- RE: analysis of YANG vs. RELAX NG Romascanu, Dan (Dan)
- Re: analysis of YANG vs. RELAX NG Leif Johansson
- RE: analysis of YANG vs. RELAX NG Romascanu, Dan (Dan)
- Re: analysis of YANG vs. RELAX NG Martin Bjorklund
- Re: analysis of YANG vs. RELAX NG Jon Saperia
- Do we need a formalized language: [Was: Re: analy… Balazs Lengyel
- Re: analysis of YANG vs. RELAX NG Balazs Lengyel
- Re: analysis of YANG vs. RELAX NG Rohan Mahy
- Re: analysis of YANG vs. RELAX NG Martin Bjorklund
- Re: analysis of YANG vs. RELAX NG Rohan Mahy
- Re: analysis of YANG vs. RELAX NG Juergen Schoenwaelder
- Re: analysis of YANG vs. RELAX NG Martin Bjorklund
- Re: analysis of YANG vs. RELAX NG Lisa Dusseault
- Re: analysis of YANG vs. RELAX NG Rohan Mahy
- Re: analysis of YANG vs. RELAX NG Juergen Schoenwaelder
- Re: analysis of YANG vs. RELAX NG Phil Shafer
- Re: analysis of YANG vs. RELAX NG Juergen Schoenwaelder
- Re: analysis of YANG vs. RELAX NG Balazs Lengyel
- Re: analysis of YANG vs. RELAX NG Balazs Lengyel
- Re: analysis of YANG vs. RELAX NG Balazs Lengyel
- Re: analysis of YANG vs. RELAX NG Balazs Lengyel
- Re: analysis of YANG vs. RELAX NG Andrew Newton
- Re: analysis of YANG vs. RELAX NG Rohan Mahy
- Re: analysis of YANG vs. RELAX NG Rohan Mahy
- Re: analysis of YANG vs. RELAX NG Balazs Lengyel
- Re: analysis of YANG vs. RELAX NG Rohan Mahy
- Re: analysis of YANG vs. RELAX NG Randy Presuhn
- Re: analysis of YANG vs. RELAX NG Juergen Schoenwaelder
- Re: analysis of YANG vs. RELAX NG Martin Bjorklund
- Re: analysis of YANG vs. RELAX NG Andy Bierman
- Re: analysis of YANG vs. RELAX NG Julian Reschke
- Re: analysis of YANG vs. RELAX NG Tim Bray
- Re: analysis of YANG vs. RELAX NG Ladislav Lhotka
- Re: analysis of YANG vs. RELAX NG Juergen Schoenwaelder
- Re: analysis of YANG vs. RELAX NG Ladislav Lhotka
- Re: analysis of YANG vs. RELAX NG Juergen Schoenwaelder
- Re: analysis of YANG vs. RELAX NG Andy Bierman
- Re: analysis of YANG vs. RELAX NG Ladislav Lhotka
- Re: analysis of YANG vs. RELAX NG Andy Bierman
- Re: analysis of YANG vs. RELAX NG Randy Presuhn
- RE: analysis of YANG vs. RELAX NG David Harrington
- RE: analysis of YANG vs. RELAX NG Romascanu, Dan (Dan)
- Re: analysis of YANG vs. RELAX NG Ladislav Lhotka
- Re: analysis of YANG vs. RELAX NG Juergen Schoenwaelder
- Re: analysis of YANG vs. RELAX NG Balazs Lengyel