Re: rmail threading

[Eli Zaretskii]

> From: Richard Stallman <rms@gnu.org>
> Cc: tomas@tuxteam.de, emacs-devel@gnu.org
> Date: Sun, 29 Aug 2021 23:01:51 -0400
> 
>   > Is the below good enough?  If it is, I can easily code a similar
>   > "previous-by-thread" command.
> 
> It is a start, but what is really needed is a summary command
> to generate a summary containing the messages of a thread established
> by message-IDs.

Ah, you want an Rmail summary command for this...  OK, will do.

In any case, my original naïve attempt was wrong, because even
sub-threads have the tree structure, they aren't linear lists.  So
we'd need a tree-traversing code, not unlike what SPC and DEL do in
Info.

> In fact, I never use rmail-next-same-subject; I don't even remember
> it is there.  I always use rmail-summary-by-topic, after which
> I can see all the messages of the thread-by-subject.

I prefer not to review a thread via a summary, because a specialized
summary prevents me from easily seeing messages that don't satisfy the
summary criteria.  This is important with criteria based on fuzzy
stuff like the Subject, because people or their MUA many times change
or mangle the Subject, and then those messages appear not to be there.
But that's me.