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->child, $level+1) if $self->child;
        dump_em($self->next, $level) if $self->next;
    }

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's happy to be handed any mail object supported by Email::Abstract. If you need to do anything else, you'll have to subclass and override _get_hdr.

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::Containers which are not the parents of any other message.

order($ordering_sub)

calls order_children over each member of the root set, from one level higher

Mail::Thread::Container methods

Mail::Thread::Containers 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.

messageid

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.

header( $name )

returns the named header of the contained message

subject

returns the subject line of the contained message

isreply

examines the results of ->subject and returns true if it looks like a reply

simple_subject

the simplified version of ->subject (with reply markers removed)

has_descendent($child)

Returns true if this container has the given container as a child somewhere beneath it.

add_child($child)

Add the $child as a child of oneself.

remove_child($child)

Remove the $child as a child from oneself.

children

Returns a list of the immediate children of this container.

set_children(@children)

set the children of a node. does not update the ->parents of the @children

order_children($ordering_sub)

Recursively reorders children according to the results of $ordering_sub

$ordering_sub is called with the containers children, and is expected to return them in their new order. 

 # order by subject line
 $container->order_children( sub {
    sort { $a->topmost->message->subject cmp $b->topmost->message->subject } @_
  } );

$ordering_sub may be omitted, in which case no ordering takes place

topmost

Walks the tree depth-first and returns the first message container found with a message attached

recurse_down($callback)

Calls the given callback on this node and all of its children.

AUTHOR

Simon Cozens, <simon@cpan.org>

COPYRIGHT AND LICENSE

Copyright 2003 by Kasei Copyright 2004 by Simon Cozens

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