Email::FolderType - Email::FolderType - determine the type of a mail folder

       Simon Wistow <simon@thegestalt.org>

       This software is copyright (c) 2005 by Simon Wistow.

       This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5
       programming language system itself.

perl v5.36.0                                       2023-07-19                             Email::FolderType(3pm)

       Currently the default matcher is "Mbox" and therefore it is always checked last and always returns 1.

       If you really want to change this then you should override "Email::FolderType::Mbox::match" and/or change
       the variable $Email::FolderType::DEFAULT to be something other than 'Mbox'.

               use Email::FolderType;
               use Email::FolderType::Mbox;

               $Email::FolderType::DEFAULT = 'NewDefault';

           package Email::FolderType::Mbox;
           sub match { return (defined $_[0] && -f $_[0]) }

               package Email::FolderType::NewDefault;
               sub match { return (defined $_[0] && $_[0] =~ m!some crazy pattern!) }
               1;

       Provides a utility subroutine for detecting the type of a given mail folder.

       Email::FolderType - Email::FolderType - determine the type of a mail folder

       "Email::FolderType" briefly flirted with a rather clunky "register_type" method for registering new
       matchers but, in retrospect that wasn't a great idea.

       Instead, in this version we've reverted to a "Module::Pluggable" based system - any classes in the
       "Email::FolderType::" namespace will be interrogated to see if they have a c<match> method.

       If they do then it will be passed the folder name. If the folder matches then the match function should
       return 1. For example ...

           package Email::FolderType::GzippedMbox;

           sub match {
               my $folder = shift;
               return (-f $folder && $folder =~ /.gz$/);
           }

           1;

       These can even be defined inline ...

           #!perl -w

           use strict;
           use Email::Folder;
           use Email::LocalDelivery;

           # copy all mail from an IMAP folder
           my $folder = Email::Folder->new('imap://example.com'); # read INBOX
           for ($folder->messages) {
               Email::LocalDelivery->deliver($_->as_string, 'local_mbox');
           }

           package Email::FolderType::IMAP;

           sub match {
               my $folder = shift;
               return $folder =~ m!^imap://!;
           }

           1;

       If there is demand for a compatability shim for the old "register_type" method then we can implement one.
       Really though, this is much better in the long run.

folder_type<path>
       Automatically detects what type of mail folder the path refers to and returns the name of that type.

       It primarily bases the type on the suffix of the path given.

         Suffix | Type
        --------+---------
         /      | Maildir
         /.     | MH
         //     | Ezmlm

       In case of no known suffix it checks for a known file structure.  If that doesn't work out it defaults to
       "Mbox" although, if the "Mbox" matcher has been overridden or the default changed (see DEFAULTMATCHER
       below) then it will return undef.

   matchers
       Returns a list of all the matchers available to the system.

         use Email::FolderType qw(folder_type);

         print folder_type "~/mymbox";     # prints 'Mbox'
         print folder_type "~/a_maildir/"; # prints 'Maildir'
         print folder_type "some_mh/.";    # prints 'MH'
         print folder_type "an_archive//"; # prints 'Ezmlm'

       version 0.814