Newsgroups: news.software.b
Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!sol.ctr.columbia.edu!ira.uka.de!smurf!urlichs
From: urlichs@smurf.sub.org (Matthias Urlichs)
Subject: Re: Thread following in newsgroups
Message-ID: <8__5i2.4nc@smurf.sub.org>
Date: Tue, 19 Mar 91 18:00:18 GMT
Distribution: news
References: <5871@acorn.co.uk>
Organization: University of Karlsruhe, FRG
Lines: 36

In news.software.b, article <5871@acorn.co.uk>,
  pcolmer@acorn.co.uk (Philip Colmer) writes:
< 
< Finally, one of the requests I've had is to try and display the articles in
< the "right" order. Due to the vagaries of the news system, it is often
< possible for a reply to arrive at our site before the original article!
< 
< So, after all that, does anyone have any logic or techniques that could be
< used in my news reader to make my thread following better?
< 
What I'm doing is:
- Any article is sorted before any article it refers to.
- Articles on the same level are sorted according to whatever the user wants.
- Missing articles inherit their search criterions from the lowest-numbered
  answer to them, for lack of better data.
- Sorting disregards the number of answers to which an article refers. It
  might make sense to sort for tree depth, but that would mean that sorting a
  new article into the list takes longer.

This gives you depth-first order, which seems reasonable.

"Whatever the user wants", above, means that my news reader allows
specification of more than one sort level. Most sorts are alphabetic; sort of
date is numeric according to getdate, sort of From address will sort by host
name first once I get around to actually implementing that, and the article
tree (References: header) sorts by tree before handing articles on the same
tree level off to the next sort level.

That approach seems to work.

NB: This news reader is called NewsView, currently in the stage of getting
    essential features (like posting) added to it, and available on the
    Macintosh.
-- 
Matthias Urlichs -- urlichs@smurf.sub.org -- urlichs@smurf.ira.uka.de     /(o\
Humboldtstrasse 7 - 7500 Karlsruhe 1 - FRG -- +49-721-621127(0700-2330)   \o)/