Re: [tlug] Thread Safe Email Programs

["Stephen J. Turnbull" <stephen@example.com>]

>>>>> "Jim" == Jim  <jep200404@example.com> writes:

    Jim> Which other email programs follows threads correctly? 

Most emacs MUAs (specifically VM, Gnus, mew, and wanderlust, and I
believe mh-e) do, although I'm pretty sure RMail does not.

I'm not sure about mh.

Sufficiently old Netscapes (cf http://www.jwz.org/doc/threading.html;
Jamie also sez and I quotez:

    This algorithm is also described in the imapext-thread Internet
    Draft: Mark Crispin and Kenneth Murchison formalized my
    description of this algorithm, and propose it as the THREAD
    extension to the IMAP protocol (the idea being that the IMAP
    server could give you back a list of messages in a pre-threaded
    state, so that it wouldn't need to be done on the client side.) If
    you find my description of this algorithm confusing, perhaps their
    restating of it will be more to your taste.

    I'm told this algorithm is also used in the Evolution and Balsa
    mail readers. Also, Simon Cozens and Richard Clamp have written a
    Perl version. (I've not tested any of these implementations, so I
    make no claims as to how faithfully they implement it.))

There are many others, I'm sure.

    Jim> What are the relevant RFCs? 

2822.  "The only RFC you'll ever need."

Really, it's not rocket science.  C'mon, Munchkins, sing with Dorothy:

"Follow the References trail,
Follow the References trail,
Follow the, follow the, follow the, follow the
Follow the References trail!"

Technically, it's just a multi-rooted topological sort (cf. tsort(1)).
The _hard_ part of the algorithms is maintaining a stable sort and
using auxiliary data like dates, required for dealing with
brain-damaged[1] mailers that don't supply thread information.

Strictly speaking, supplying thread information is not required by any
RFC, nor is using it.  But I don't see any good reason why people
whose MUAs do threading correctly shouldn't take advantage of that to
improve the quality of the human-readable labels (aka Subject field).
It's simply a matter of whether you care more about accurate phrasing
or the readability to people with MUAs-that-suck[tm], and that is a
judgment call that will vary from situation to situation.  (Sorry, Ian.)


Footnotes: 
[1]  A well-defined technical term used by PhDs in the field, so don't
get your PC backs up.

Cf. http://catb.org/~esr/jargon/html/B/brain-damaged.html.

-- 
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