Re: [netmod] default namespace in XPath

Ladislav Lhotka <lhotka@nic.cz> Wed, 07 March 2018 11:34 UTC

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From: Ladislav Lhotka <lhotka@nic.cz>
To: Michal =?UTF-8?Q?Va=C5=A1ko?= <mvasko@cesnet.cz>
Cc: NETMOD WG <netmod@ietf.org>
Date: Wed, 07 Mar 2018 12:34:12 +0100
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Subject: Re: [netmod] default namespace in XPath
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Hi Michal,

On Wed, 2018-03-07 at 10:18 +0100, Michal Vaško wrote:
> Hello,
> we have implemented it as option 1 based on the "current()" function 

Right, I have the same in my implementation. It is however counter-intuitive in
cases like my example because unprefixed names normally receive the namespace of
the module where they appear (I made a mistake myself:-).

> definition (RFC 7950 sec. 10.1.1):
> 
> The current() function takes no input parameters and returns a node
>    set with the initial context node as its only member.
> 
> If this was not intended and actually option 2 is correct, the "current()"
> function should probably be renamed or return a different node to be
> consistent and not misleading.

IMO the current() function should stay, but the text in sec. 6.4.1 has to be
changed:

OLD
  Names without a namespace prefix belong to the same namespace as
  the identifier of the current node.

NEW
  Names without a namespace prefix belong to the same namespace as
  the identifier of the context node.

If there are no objections, I will file an erratum.

Lada

> 
> Regards,
> Michal
> 
> On Wednesday, March 7, 2018 10:11 CET, Ladislav Lhotka <lhotka@nic.cz> wrote: 
>  
> > Hi,
> > 
> > sec. 6.4.1 in RFC 7950 says in the second bullet item:
> > 
> >     Names without a namespace prefix belong to the same namespace as
> >     the identifier of the current node.
> > 
> > It is unclear what "current node" means:
> > 
> > 1. Is it the context node of the XPath expression, or
> > 
> > 2. is it the schema node corresponding to the parent statement of the
> > must/when
> > statement?
> > 
> > For example:
> > 
> > module example-4-a {
> >   ...
> >   container bag {
> >     ...
> >   }
> > }
> > 
> > module example-4-b {
> >   ...
> >   import example-4-a {
> >     prefix "ex4a";
> >   }
> > 
> >   augment "/ex4a:bag" {
> >     when "/quux = 0";
> >     ...
> >     }
> >   }
> >   ...
> > }
> > 
> > What is the namespace of "quux" in the when expression? Is it "example-4-a"
> > (option 1 above) or "example-4-b" (option 2)?
> > 
> > Thanks, 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