NAME
    List::AutoNumbered - Add sequential numbers to lists while creating them

    This module adds sequential numbers to lists of lists so you don't have to
    type all the numbers.  Its original use case was for adding line numbers
    to lists of testcases.  For example:

        use List::AutoNumbered;                             # line 1
        my $list = List::AutoNumbered->new(__LINE__);       # line 2
        $list->load("a")->                                  # line 3
            ("b")                                           # line 4
            ("c")                                           # line 5
            ("d");                                          # line 6

        # Now $list->arr is [ [3,"a"], [4,"b"], [5,"c"], [6,"d"] ]

    In general, you can pass any number to the constructor.  For example:

        use List::AutoNumbered;
        use Test::More tests => 1;

        my $list = List::AutoNumbered->new;     # First entry will be number 1
        $list->load("a")->      # Yes, trailing arrow
            ("b")               # Magic!  Don"t need any more arrows!
            ("c")
            ("d");

        is_deeply($list->arr, [
            [1, "a"], [2, "b"], [3, "c"], [4, "d"]
        ]);     # Yes, it is!

METHODS
  new
    Constructor.  Basic usage options:

        $list = List::AutoNumbered->new();      # first list item is number 1
        $list = List::AutoNumbered->new($num);  # first list item is $num+1
        $list = List::AutoNumbered->new(-at => $num);   # ditto

    Each successive element will have the next number, unless you say
    otherwise (e.g., using LSKIP()).  Specifically, the first item in the list
    will be numbered one higher than the number passed to the
    "List::AutoNumbered" constructor.

    Constructor parameters are processed using Getargs::Mixed, so positional
    and named parameters are both OK.

   The "how" function
    You can give the constructor a "how" function that will make the list
    entry for a single load() or add() call:

        $list = List::AutoNumbered->new(-how => sub { @_ });
            # Jam everything together to make a flat array
        $list = List::AutoNumbered->new(41, sub { @_ });
            # Positional is OK, too.

    The "how" function is called as "how($num, @data)".  $num is the line
    number for load() calls, or "undef" for add() calls.  @data is whatever
    data you passed to "load()" or "add()".  For example, the default "how"
    function is:

        sub how {
            shift unless defined $_[0];     # add passes undef as the line number.
            [@_]                            # Wrap everything in an arrayref.
        }

    See "t/05-custom-list-entry.t" for examples of custom "how" functions.

  size
    Returns the size of the array.  Like "scalar @arr".

  last
    Returns the index of the last element in the array.  Like $#array.

  arr
    Returns a reference to the array being built.  Please do not modify this
    array directly until you are done loading it.  List::AutoNumbered may not
    work if you do.

  last_number
    Returns the current number stored by the instance.  This is the number of
    the most recently preceding new() or load() call.  This is not the number
    that will be given to the next record, since that depends on whether or
    not the next record has a skip (LSKIP()).

  load
    Push a new record with the next number on the front.  Usage:

        $instance->load(whatever args you want to push);

    Or, if the current record isn't associated with the number immediately
    after the previous record,

        $instance->load(LSKIP $n, args);

    where $n is the number of lines between this "load()" call and the last
    one.

    Returns a coderef that you can call to chain loads.  For example, this
    works:

        $instance->load(...)->(...)(...)(...) ... ;
        # You need an arrow ^^ here, but don't need any after that.

  add
    Add to the array being built, without inserting the number on the front. 
    Does increment the number and respect skips, for consistency.

    Returns the instance.

FUNCTIONS
  LSKIP
    A convenience function to create a skipper.  Prototyped as "($)" so you
    can use it conveniently with load():

        $instance->load(LSKIP 1, whatever args...);

    If you are using line numbers, the parameter to "LSKIP" should be the
    number of lines above the current line and below the last new() or load()
    call.  For example:

        my $instance = List::AutoNumbered->new(__LINE__);
        # A line
        # Another one
        $instance->load(LSKIP 2,    # two comment lines between new() and here
                        'some data');

INTERNAL PACKAGES
  List::AutoNumbered::Skipper
    This package represents a skip and is created by LSKIP().  No
    user-serviceable parts inside.

   new
    Creates a new skipper.  Parameters are for internal use only and are not
    part of the public API.

GLOBALS
  $TRACE
    (Default falsy) If truthy, print trace output.  Must be accessed directly
    unless requested on the "use" line.  Either of the following works:

        use List::AutoNumbered; $List::AutoNumbered::TRACE=1;
        use List::AutoNumbered q(*TRACE); $TRACE=1;

AUTHOR
    Christopher White, "<cxwembedded at gmail.com>"

BUGS
    Please report any bugs or feature requests through the web interface at
    <https://github.com/cxw42/List-AutoNumbered/issues>.  I will be notified,
    and then you'll automatically be notified of progress on your bug as I
    make changes.

SUPPORT
    You can find documentation for this module with the perldoc command.

        perldoc List::AutoNumbered

    You can also look for information at:

    *   MetaCPAN

        <https://metacpan.org/pod/List::AutoNumbered>

    *   CPAN Ratings

        <https://cpanratings.perl.org/d/List-AutoNumbered>

ACKNOWLEDGEMENTS
    Thanks to zdim <https://stackoverflow.com/users/4653379/zdim> for
    discussion and ideas in the Stack Overflow question
    <https://stackoverflow.com/q/50510809/2877364> that was the starting point
    for this module.

LICENSE AND COPYRIGHT
    Copyright 2019 Christopher White.

    This program is free software; you can redistribute it and/or modify it
    under the terms of either: the GNU General Public License as published by
    the Free Software Foundation; or the Artistic License.

    See <http://dev.perl.org/licenses/> for more information.

