NAME

Tie::Autotie - Automatically ties underlying references

SYNOPSIS

      use Tie::Autotie
        'Tie::Module',      # the module to autotie
        [ 'use', 'args' ],  # arguments to 'use Tie::Module'
        [ 'tie', 'args' ];  # arguments to tie() for Tie::Module

      # then use Tie::Module as usual

DESCRIPTION

This module allows you to automatically tie data structures contained in a tied data structure. As an example:

use Tie::Autotie 'Tie::IxHash';

tie my(%hash), 'Tie::IxHash';

      $hash{jeff}{age} = 22;
      $hash{jeff}{lang} = 'Perl';
      $hash{jeff}{brothers} = 3;
      $hash{jeff}{sisters} = 4;

      $hash{kristin}{age} = 22;
      $hash{kristin}{lang} = 'Latin';
      $hash{kristin}{brothers} = 1;
      $hash{kristin}{sisters} = 0;

      for my $who (keys %hash) {
        print "$who:\n";
        for my $what (keys %{ $hash{$who} }) {
          print "  $what = $hash{$who}{$what}\n";
        }
      }

This program outputs:

jeff

age = 22 lang = Perl brothers = 3 sisters = 4

kristin

age = 22 lang = Latin brothers = 1 sisters = 0

You can see that the keys of %hash are returned in the order in which they were created, as well as the keys of the sub-hashes.

BUGS

• A non-autotied layer It only works if each layer is being autotied. As soon as there's a layer that is not being autotied, all layers inside it will also be

  ignored

  use Tie::Autotie 'Tie::IxHash';

tie my(%hash), 'Tie::IxHash';

          $hash{a}{b} = 1;  # %{ $hash{a} } is autotied
          $hash{a}{c} = 2;  # so keys %{ $hash{a} } returns ('b', 'c')
  
          $hash{d}[0]{a}{y} = 3;  # %{ $hash{d} } is autotied, but Tie::IxHash has
          $hash{d}[0]{a}{x} = 4;  # no control over $hash{d}[0], so $hash{d}[0]{a}
                                  # is not autotied

        At the moment, there's no way to get around this. Please stick to
        using data structures that your tying module can handle.

• Assigning a reference In the Tie::IxHash example, you cannot do:

          $hash{jeff} = {
            age => 22,
            lang => 'Perl',
            brothers => 3,
            sisters => 4,
          };

        because that creates a hash reference, not an object of Tie::IxHash.
        This hash reference ends up being destroyed anyway, and replaced
        with a Tie::IxHash object that points to an empty hash.

AUTHOR

Jeff "japhy" Pinyan, <japhy@pobox.com>

COPYRIGHT AND LICENSE

Copyright (C) 2004 by japhy

        This library is free software; you can redistribute it and/or modify
        it under the same terms as Perl itself, either Perl version 5.8.3
        or, at your option, any later version of Perl 5 you may have
        available.