in reply to Case insensitivity in a hash... Futile effort?

Here's a Tie module you can use to recursively implement the Tie::CaseInsensitive module on hash values that are hash references (so you don't need to keep tie()ing). 
package Tie::RecursiveCI;

use strict;
use Tie::CaseInsensitive;
use vars qw( @ISA );

@ISA = qw( Tie::CaseInsensitive );


sub STORE {
  my ($self, $key, $value) = @_;
  $self->{lc $key} = $value;
  if (UNIVERSAL::isa($value,'HASH')) {
    tie %{ $self->{lc $key} }, 'Tie::RecursiveCI';
  }
  return $self->{lc $key};
}

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Here's a sample program using it: 
#!/usr/bin/perl

use Tie::RecursiveCI;
tie %hash, 'Tie::RecursiveCI';

$hash{foo} = 10;
$hash{Foo} = 20;
$hash{bar}{blat} = 30;
$hash{BAR}{blAT} = 40;

for (sort keys %hash) {
  print "$_ => $hash{$_}\n";
}

for (sort keys %{ $hash{bAr} }) {
  print "$_ => $hash{bar}{$_}\n";
}

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And here's the output: 
bar => HASH(0xd67b0)
foo => 20
blat => 40

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In Section Seekers of Perl Wisdom