NAME
   Mail::Thread - Perl implementation of JWZ's mail threading algorithm

SYNOPSIS
       use Mail::Thread;
       my $threader = new Mail::Thread (@messages);

       $threader->thread;

       dump_em($_,0) for $threader->rootset;

       sub dump_em {
           my ($self, $level) = @_;
           print (' \\-> ' x $level);
           if ($self->message) {
               print $self->message->head->get("Subject") , "\n";
           } else {
               print "[ Message $self not available ]\n";
           }
           dump_em($self->next, $level) if $self->next;
           dump_em($self->child, $level+1) if $self->child;
       }

DESCRIPTION
   This module implements something relatively close to Jamie Zawinski's
   mail threading algorithm, as described by
   http://www.jwz.org/doc/threading.html. Any deviations from the algorithm
   are accidental.

   It doesn't do threading by subject yet, because I don't need it yet.

   It's happy to be handed "Mail::Internet" and "Mail::Box::Message"
   objects, since they're more or less the same, but nothing other than
   that.

METHODS
 new(@messages)
   Creates a new threader; requires a bunch of messages to thread.

 thread
   Goes away and threads the messages together.

 rootset
   Returns a list of "Mail::Thread::Container"s which are not the parents
   of any other message.

"Mail::Thread::Container" methods
   "Mail::Thread::Container"s are the nodes of the thread tree. You can't
   just have the ordinary messages, because we might not have the message
   in question. For instance, a mailbox could contain two replies to a
   question that we haven't received yet. So all "logical" messages are
   stuffed in containers, whether we happen to have that container or not.

   To do anything useful with the thread tree, you're going to have to
   recurse around the list of "Mail::Thread::Containers". You do this with
   the following methods:

 parent
 child
 next
   Returns the container which is the parent, child or immediate sibling of
   this one, if one exists.

 message
   Returns the message held in this container, if we have one.

 id
   Returns the message ID for this container. This will be around whether
   we have the message or not, since some other message will have referred
   to it by message ID.

 find_child($child)
   Returns true if this container has the given container as a child
   somewhere beneath it.

 children
   Returns a list of the immediate children of this container.

 recurse_down($callback)
   Calls the given callback on this node and all of its children.

AUTHOR
   Simon Cozens, <[email protected]>

COPYRIGHT AND LICENSE
   Copyright 2003 by Kasei

   This library is free software; you can redistribute it and/or modify it
   under the same terms as Perl itself.