NAME
    Mail::Message::Subject - utilities to manipulate subject string.

SYNOPSIS
        my $subject = new Mail::Message::Subject $header->get('subject');
        $subject->mime_header_decode();
        if ($subject->has_reply_tag()) {
            $subject->delete_dup_reply_tag();
        }
        $subject->mime_header_encode();
        $header->set($subject->as_str());

DESCRIPTION
  new($subject)
    constructor.

Re: TAG HANLING
ML TAG HANDLING
  regexp_compile()
    create the regexp for a subject tag, for example "[%s %05d]" => "\[\S+
    \d+\]".

CODING STYLE
    See "http://www.fml.org/software/FNF/" on fml coding style guide.

AUTHOR
    Ken'ichi Fukamachi

COPYRIGHT
    Copyright (C) 2004,2005 Ken'ichi Fukamachi

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

HISTORY
    Mail::Message::Subject first appeared in fml8 mailing list driver
    package. See "http://www.fml.org/" for more details.

    "Subject_to_unixtime" is imported from fml 4.0-current libmti.pl.