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.