-#
-# Tie/RefHash.pm - use references as hash keys
-#
-# Documentation at the __END__
-#
-
-require 5.004;
package Tie::RefHash;
+
+our $VERSION = '1.3_00';
+
+=head1 NAME
+
+Tie::RefHash - use references as hash keys
+
+=head1 SYNOPSIS
+
+ require 5.004;
+ use Tie::RefHash;
+ tie HASHVARIABLE, 'Tie::RefHash', LIST;
+ tie HASHVARIABLE, 'Tie::RefHash::Nestable', 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. Normally, only the
+keys of the tied hash itself are preserved as references; to use
+references as keys in hashes-of-hashes, use Tie::RefHash::Nestable,
+included as part of Tie::RefHash.
+
+It is implemented using the standard perl TIEHASH interface. Please
+see the C<tie> entry in perlfunc(1) and perltie(1) for more information.
+
+The Nestable version works by looking for hash references being stored
+and converting them to tied hashes so that they too can have
+references as keys. This will happen without warning whenever you
+store a reference to one of your own hashes in the tied hash.
+
+=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";
+ }
+
+ tie %h, 'Tie::RefHash::Nestable';
+ $h{$a}->{$b} = 1;
+ for (keys %h, keys %{$h{$a}}) {
+ print ref($_), "\n";
+ }
+
+=head1 AUTHOR
+
+Gurusamy Sarathy gsar@activestate.com
+
+=head1 VERSION
+
+Version 1.3
+
+=head1 SEE ALSO
+
+perl(1), perlfunc(1), perltie(1)
+
+=cut
+
use Tie::Hash;
+use vars '@ISA';
@ISA = qw(Tie::Hash);
use strict;
sub FETCH {
my($s, $k) = @_;
- (ref $k) ? $s->[0]{"$k"}[1] : $s->[1]{$k};
+ if (ref $k) {
+ if (defined $s->[0]{"$k"}) {
+ $s->[0]{"$k"}[1];
+ }
+ else {
+ undef;
+ }
+ }
+ else {
+ $s->[1]{$k};
+ }
}
sub STORE {
sub FIRSTKEY {
my $s = shift;
- my $a = scalar(keys %{$s->[0]}) + scalar(keys %{$s->[1]});
+ keys %{$s->[0]}; # reset iterator
+ keys %{$s->[1]}; # reset iterator
$s->[2] = 0;
$s->NEXTKEY;
}
%{$s->[1]} = ();
}
-1;
-
-__END__
-
-=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)
+package Tie::RefHash::Nestable;
+use vars '@ISA';
+@ISA = 'Tie::RefHash';
+sub STORE {
+ my($s, $k, $v) = @_;
+ if (ref($v) eq 'HASH' and not tied %$v) {
+ my @elems = %$v;
+ tie %$v, ref($s), @elems;
+ }
+ $s->SUPER::STORE($k, $v);
+}
-=cut
+1;