#!/usr/local/bin/perl -w
# tie-refhash.pl -- Referenzen als Schluessel in Hashes

use Tie::RefHash;                # Standardmodul
use strict 'refs';               # Keine symbolische Referenzen!

$node = { VALUE => 'xyzzy' };
$changeme = "change me!";

tie %ts, 'Tie::RefHash';

$ts{ [] }                       = "The Array";
$ts{ {} }                       = "The Hash";
$ts{ \substr($changeme, 0, 6) } = "An lvalue!";
$ts{ sub { exit 0; } }          = "Anonymous subroutine!";
$ts{ \*STDIN }                  = "This is stdin!";
$ts{ $node }                    = "VISITED";
$ts{ \@ARGV }                   = 'This is Array @ARGV!';

while (($key,$val) = each %ts) {
    print "Found: $key",
          ", Type: " ,  ref($key),
          ", Value: ",  $val, "\n";

    push(@{$key}, qw(not empty anymore)) if $val eq 'The Array';
    $key->{'firstkey'} = 'first value'   if $val eq 'The Hash';
    ${$key} = 'try'                      if $val eq 'An lvalue!';
    print "node visited...\n"            if $key == $node
                                                 and
                                     exists $key->{'VISITED'};
}
print "new changeme: >$changeme<\n";

use Data::Dumper;
print Dumper(grep { ref($_) ne 'LVALUE' } keys %ts);

untie %ts;