—

              
package Tie::RefHash;
HideShow 51 lines of Pod
=head1 NAME
Tie::RefHash - use references as hash keys
=head1 SYNOPSIS
    require 5.004;
    use Tie::RefHash;
    tie HASHVARIABLE, 'Tie::RefHash', LIST;
    untie HASHVARIABLE;
=head1 DESCRIPTION
This module provides the ability to use references as hash keys if
you first C<tie> the hash variable to this module.
It is implemented using the standard perl TIEHASH interface.  Please
see the C<tie> entry in perlfunc(1) and perltie(1) for more information.
=head1 EXAMPLE
    use Tie::RefHash;
    tie %h, 'Tie::RefHash';
    $a = [];
    $b = {};
    $c = \*main;
    $d = \"gunk";
    $e = sub { 'foo' };
    %h = ($a => 1, $b => 2, $c => 3, $d => 4, $e => 5);
    $a->[0] = 'foo';
    $b->{foo} = 'bar';
    for (keys %h) {
       print ref($_), "\n";
    }
=head1 AUTHOR
Gurusamy Sarathy        gsar@umich.edu
=head1 VERSION
Version 1.2    15 Dec 1996
=head1 SEE ALSO
perl(1), perlfunc(1), perltie(1)
=cut
require 5.003_11;
use Tie::Hash;
@ISA = qw(Tie::Hash);
use strict;
sub TIEHASH {
  my $c = shift;
  my $s = [];
  bless $s, $c;
  while (@_) {
    $s->STORE(shift, shift);
  }
  return $s;
}
sub FETCH {
  my($s, $k) = @_;
  (ref $k) ? $s->[0]{"$k"}[1] : $s->[1]{$k};
}
sub STORE {
  my($s, $k, $v) = @_;
  if (ref $k) {
    $s->[0]{"$k"} = [$k, $v];
  }
  else {
    $s->[1]{$k} = $v;
  }
  $v;
}
sub DELETE {
  my($s, $k) = @_;
  (ref $k) ? delete($s->[0]{"$k"}) : delete($s->[1]{$k});
}
sub EXISTS {
  my($s, $k) = @_;
  (ref $k) ? exists($s->[0]{"$k"}) : exists($s->[1]{$k});
}
sub FIRSTKEY {
  my $s = shift;
  my $a = scalar(keys %{$s->[0]}) + scalar(keys %{$s->[1]});
  $s->[2] = 0;
  $s->NEXTKEY;
}
sub NEXTKEY {
  my $s = shift;
  my ($k, $v);
  if (!$s->[2]) {
    if (($k, $v) = each %{$s->[0]}) {
      return $s->[0]{"$k"}[0];
    }
    else {
      $s->[2] = 1;
    }
  }
  return each %{$s->[1]};
}
sub CLEAR {
  my $s = shift;
  $s->[2] = 0;
  %{$s->[0]} = ();
  %{$s->[1]} = ();
}
1;