From: urlichs@smurf.sub.org (Matthias Urlichs)
Newsgroups: news.software.readers,news.software.b
Subject: Re: DESIGN DISCUSSION: The reference line is deficient
Date: 30 Dec 1992 20:44:53 +0100
Organization: University of Karlsruhe, FRG
NNTP-Posting-Host: 127.0.0.1

In news.software.b, article <C02wp5.8JB@mtholyoke.edu>,
  jbotz@mtholyoke.edu (Jurgen Botz) writes:
> In article <1hro2sINNo54@daisy.ee.und.ac.za> barrett@daisy.ee.und.ac.za (Alan P Barrett) writes:
> >Why change the format at all?  The 'R' tells you nothing that you don't
> >alread know from the mere fact that it is the first reference on the line.
> >You can get the same result by using
> >
> >     References: <root@id> <old@references> <last@id>
> >
> >where the <root@id> is always propagated from an article to its followup,
> >but some of the <old@references> might be trimmed during a followup.
> 
> Yes, that's nice, but in many cases it isn't true. The idea behind the
> "R<id>" format is that trn needs to be able to know when it can reliably
> identify a particular <id> as being that of the root of the thread.
> 
But an R<ID> or an X-_anything_:-header doesn't give you a useable ID
either -- if the association of a subtree to its parent is lost,
it's gone no matter whether somebody failed to propagate an X-Root:-
header or whether the first ID of References: got deleted.

> >Don't change the format.  Encourage authors of posting software to
> >ensure that the first reference is always retained.  Lobby for this
> >encouragement to be enshrined in the son-of-RFC1036.
> 
> I'm all for that myself... but in practice we'll never arrive at a
> situation where all posts are generated by conformant readers.

No, but we can get closer. We can get more close with a more stable standard.
Declaring the first ID to be inherently magical therefore is better than
something that has to be added to every newsreader in existence (X-RootID:)
or which breaks existing standards (References: R<ID>).

> Therefor programs which want to utilize this information need to be
> able to tell the difference.
> 
In my experience, article trees get split up because people post via mail
or BBS gateways. You won't solve that problem with inventing another 
mechanism to identify root IDs.

> Aha... this suggests a third solution!  If soRFC1036 explicitly stated
> that the first <id> in the 'References:' header is to be the root,
> then we could add an 'X-soRFC1036-conformat: yes' header to get the
> same benefits!

I fail to see any reason why you need to uniquely identify anything.

You have a subtree, that subtree has a root, you kill the subtree. No problem.

Problems show up when you combine identify-by-subtree with other mechanisms,
like identify-by-common-subject. But what's wrong with (temporarily) adding
the subject line to the kill file too?

> So of the solutions outlined by Wayne I would prefer the 'X-Root:'
> one.
> 
I don't. That header isn't even propagated into replies by most news readers,
thus you would have to change all readers. Only some readers mangle References:
lines at all; always preserving the first ID should be a trivial change.

-- 
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-- 
Matthias Urlichs  --  urlichs@smurf.sub.org -- urlichs@smurf.ira.uka.de   /(o\
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Newsgroups: news.software.readers