SYNOPSIS

     use Sort::Sub qw($naturally);
    
     my @sorted = sort $naturally ('track1.mp3', 'track10.mp3', 'track2.mp3', 'track1b.mp3', 'track1a.mp3');
     # => ('track1.mp3', 'track1a.mp3', 'track1b.mp3', 'track2.mp3', 'track10.mp3')

    Request as subroutine:

     use Sort::Sub qw(naturally);
    
     my @sorted = sort {naturally} (...);

    Request a reverse sort:

     use Sort::Sub qw($naturally<r>);
    
     my @sorted = sort $naturally (...);
     # => ('track10.mp3', 'track2.mp3', 'track1b.mp3', 'track1a.mp3', 'track1.mp3')

    Request a case-insensitive sort:

     use Sort::Sub qw($naturally<i>);
    
     my @sorted = sort $naturally (...);

    Request a case-insensitive, reverse sort:

     use Sort::Sub qw($naturally<ir>;
    
     my @sorted = sort $naturally ('track2.mp3', 'Track1.mp3', 'Track10.mp3');
     => ('Track10.mp3', 'track2.mp3', 'Track1.mp3')

    Use with

DESCRIPTION

    Sort::Sub and Sort::Sub::* are a convenient packaging of any kind of
    subroutine which you can use for sort().

    To use Sort::Sub, you import a list of:

     ["$"]NAME [ "<" [i][r] ">" ]

    Where NAME is actually searched under Sort::Sub::* namespace. For
    example:

     naturally

    will attempt to load Sort::Sub::naturally module and call its
    gen_sorter subroutine.

    You can either request a subroutine name like the above or a variable
    name (e.g. $naturally).

    After the name, you can add some options, enclosed with angle brackets
    <>. There are some known options, e.g. i (for case-insensitive sort) or
    r (for reverse sort). Some examples:

     naturally<i>
     naturally<r>
     naturally<ri>

GUIDELINES FOR WRITING A SORT::SUB::* MODULE

    The name should be in lowercase. It should be an adverb (e.g.
    naturally) or a phrase with words separated by underscore (_) and the
    phrase begins with by (e.g. by_num_and_non_num_parts).

    The module must contain a gen_sorter subroutine. It will be called
    with:

     ($is_reverse, $is_ci)

    Where $is_reserve will be set to true if user requests a reverse sort,
    and $is_ci will be set to true if user requests a case-insensitive
    sort. The subroutine should return a code reference.