On Wed 02 Nov 2011 04:37:05 PM EET, Austin Clements wrote:

 > On Mon, Oct 31, 2011 at 7:07 PM, Florian Friesdorf <flo@chaoflow.net> wrote:
 > >
 > > Hi,
 > >
 > > I'm looking into taking the References header into account for thread
 > > ordering. So far only In-Reply-To is used. My C/C++ is rusty at best, so
 > > I'd need some help to get this done.

<snip>
 
 > I know this came up on IRC, but have you looked at jwz's threading
 > algorithm (http://www.jwz.org/doc/threading.html)?  Carl mentioned
 > that notmuch already implements it (except for subject matching), but
 > notmuch only implements the subset of it necessary to group messages
 > into threads without structure.  Much of the algorithm is devoted to
 > exactly this problem of piecing together the thread structure based on
 > all of the information in both In-Reply-To and References.  The
 > algorithm as described combines the issues of grouping and structuring
 > since it's expecting a giant pile of mail as input, but there's no
 > reason these can't be teased apart.

I've implemented it for mu[1], maybe some of it can be reusable for notmuch;
see mu-threader.[ch] and mu-container.[ch] in

   http://gitorious.org/mu/mu/blobs/master/src/

(starting point is mu_threader_calculate).
   
I didn't implement subject matching yet, but it does build the hierarchy as
per JWZ and "References:".

Best wishes,
Dirk.

-- 
Dirk-Jan C. Binnema                  Helsinki, Finland
e:djcb@djcbsoftware.nl           w:www.djcbsoftware.nl
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