Re: Fw: Comments on LDP-Paging - 5.1.5 whole != sum(parts)

On Thu, Jul 31, 2014 at 12:12 PM, John Arwe <johnarwe@us.ibm.com> wrote:

> Moving SS reply on-list.
>
Didn't intend for that, so thanks for putting it back.


>
> wrt union, all I'm saying is: since LDP Paging only defines how to combine
> pages when the paged resource is a LDP-RS, 'union' is not going to be
> necessarily the right operation for all LDPRs.  If I think about using this
> in Google Maps (each tile = 1 page), it's obviously *the wrong* operation
> no matter how you define union in any commonly understood way.  Yet it
> seems like a perfectly sensible use of Paging, were those folks so inclined
> (disclaimer: I don't work for that company, don't know anyone in that dev
> group, and so on - purely speculative example on my part.)
>
> I did verify that the current text is a straight copy from 5005 paged
> feeds.  Given that LDP Paging adds canonical etags as a way for clients to
> detect when the container changed, which paged feeds have no equivalent
> for, it is overly pessimistic now (but not when it was copied).  There's
> also a language mapping error (paged resource ~= logical feed, not paged
> feed) that we can fix given the updates I made earlier this week, wherein
> 'page sequence' (which had crept into the draft via the email discussions)
> was promoted to a formally defined term.
>
> Strawman revision:
>
> 5.1.5 LDP Paging clients SHOULD NOT treat a page sequence as equivalent to
> the paged resource when the _paged resource changed_ [link to 6.2.8]
> _during retrieval of the page sequence_ [link to 6.2.7].
>
>
> I'm tempted to say Must Not, given the addition of the "changed"
> qualification vs 5005, but I can live with either.  Can anyone NOT live
> with Must Not?  Keep in mind this is a constraint on LDP Paging clients,
> not servers.
>
> I think the wording is fine and SHOULD NOT sends the right message.  MUST
NOT is hard to test compliance to anyway.

- Steve

> Best Regards, John
>
> Voice US 845-435-9470  BluePages
> <http://w3.ibm.com/jct03019wt/bluepages/simpleSearch.wss?searchBy=Internet+address&location=All+locations&searchFor=johnarwe>
> Cloud and Smarter Infrastructure OSLC Lead
>
> ----- Forwarded by John Arwe/Poughkeepsie/IBM on 07/31/2014 10:35 AM -----
>
> From:        Steve Speicher <sspeiche@gmail.com>
> To:        John Arwe/Poughkeepsie/IBM@IBMUS
> Date:        07/30/2014 04:19 PM
> Subject:        Re: Comments on LDP-Paging - 5.1.5 whole != sum(parts)
> ------------------------------
>
>
>
> On Tue, Jul 29, 2014 at 4:37 PM, John Arwe <*johnarwe@us.ibm.com*
> <johnarwe@us.ibm.com>> wrote:
> >
> > > <#ldpp-client-paging-incomplete>
> > > I find this normative statement hard to understand, at all:
> > > [[5.1.5 LDP Paging clients SHOULD NOT present paged resources as
> > > coherent or complete, or make assumptions to that effect.]]
> > > I'm having a hard time with the words "present", "coherent" and
> > > "complete" in this clause.
> > >
> > > I would think a clause such as this might make more sense:
> > > [[5.1.5 LDP Paging clients SHOULD NOT present a union of all in-
> > > sequence page resource representations as equivalent to the
> > > representation for the paged resource.]]
> >
> > The proposed(?) update doesn't work for all LDPRs, does it?  It could be
> a useful example for LDP-RSs in particular, modulo using the more specific
> "graph union".
> Why doesn't it work for all LDPRs, union in the proposed doesn't define it
> anything more than the normal mathematical term.
>
> > I suspect the words that do so offend are carryovers from 5005, I'd have
> to check that.  "present" might be WebArch.
> > "equivalent" ... 3986 chapter 5 -veined issues.
> >
> Hoping that "equivalent to the representation" would get what you were
> after.  So I would think equivalence would be defined by each of the
> representations.
>
> If I were a client implementor, to comply I would have to present the
> paged resource as incoherent or incomplete.  An end user wouldn't like that
> and not use my client anymore.  Therefore I would probably just present it
> as "built from parts"; does this pass the compliance (SHOULD NOT) test of
> not-complete and not-coherent? I'm not sure.  The way I proposed to modify
> it, then yes I think I would understand I'm inline with the spec.
>
> > At a higher level though, this was probably last visited before we had
> canonical etags, so apropos some of your other "this sounds scarier than it
> needs to" comments perhaps we could be more accurate.
> >
> Yes, my reaction of "this sounds scarier  than it needs to be".  Though
> I'm losing how canonical etags softens it the way it was written.  Maybe
> that is not what you saying.
>
> Have others weighed in?  Haven't seen anything on the list, I would like
> something "less scary" for LDP paging clients to have to present in order
> to conform.
>
> Thanks,
> Steve Speicher
> *http://stevespeicher.me* <http://stevespeicher.me/>
>
>
> > [1]
> *http://lists.w3.org/Archives/Public/public-ldp-wg/2014Jul/0059.html*
> <http://lists.w3.org/Archives/Public/public-ldp-wg/2014Jul/0059.html>
> >
> > Best Regards, John
> >
> > Voice US 845-435-9470  BluePages
> > Cloud and Smarter Infrastructure OSLC Lead
> >
>
>