Commit | Line | Data |
---|---|---|
5f05dabc | 1 | package Tie::RefHash; |
2 | ||
b75c8c73 MS |
3 | our $VERSION = '1.21'; |
4 | ||
5f05dabc | 5 | =head1 NAME |
6 | ||
7 | Tie::RefHash - use references as hash keys | |
8 | ||
9 | =head1 SYNOPSIS | |
10 | ||
11 | require 5.004; | |
12 | use Tie::RefHash; | |
13 | tie HASHVARIABLE, 'Tie::RefHash', LIST; | |
778e8f97 | 14 | tie HASHVARIABLE, 'Tie::RefHash::Nestable', LIST; |
5f05dabc | 15 | |
16 | untie HASHVARIABLE; | |
17 | ||
18 | =head1 DESCRIPTION | |
19 | ||
778e8f97 EA |
20 | This module provides the ability to use references as hash keys if you |
21 | first C<tie> the hash variable to this module. Normally, only the | |
22 | keys of the tied hash itself are preserved as references; to use | |
23 | references as keys in hashes-of-hashes, use Tie::RefHash::Nestable, | |
24 | included as part of Tie::Hash. | |
5f05dabc | 25 | |
26 | It is implemented using the standard perl TIEHASH interface. Please | |
27 | see the C<tie> entry in perlfunc(1) and perltie(1) for more information. | |
28 | ||
778e8f97 EA |
29 | The Nestable version works by looking for hash references being stored |
30 | and converting them to tied hashes so that they too can have | |
31 | references as keys. This will happen without warning whenever you | |
32 | store a reference to one of your own hashes in the tied hash. | |
33 | ||
5f05dabc | 34 | =head1 EXAMPLE |
35 | ||
36 | use Tie::RefHash; | |
37 | tie %h, 'Tie::RefHash'; | |
38 | $a = []; | |
39 | $b = {}; | |
40 | $c = \*main; | |
41 | $d = \"gunk"; | |
42 | $e = sub { 'foo' }; | |
43 | %h = ($a => 1, $b => 2, $c => 3, $d => 4, $e => 5); | |
44 | $a->[0] = 'foo'; | |
45 | $b->{foo} = 'bar'; | |
46 | for (keys %h) { | |
47 | print ref($_), "\n"; | |
48 | } | |
49 | ||
778e8f97 EA |
50 | tie %h, 'Tie::RefHash::Nestable'; |
51 | $h{$a}->{$b} = 1; | |
52 | for (keys %h, keys %{$h{$a}}) { | |
53 | print ref($_), "\n"; | |
54 | } | |
5f05dabc | 55 | |
56 | =head1 AUTHOR | |
57 | ||
da41ffc5 | 58 | Gurusamy Sarathy gsar@activestate.com |
5f05dabc | 59 | |
60 | =head1 VERSION | |
61 | ||
da41ffc5 | 62 | Version 1.21 22 Jun 1999 |
5f05dabc | 63 | |
64 | =head1 SEE ALSO | |
65 | ||
66 | perl(1), perlfunc(1), perltie(1) | |
67 | ||
68 | =cut | |
69 | ||
70 | require 5.003_11; | |
71 | use Tie::Hash; | |
72 | @ISA = qw(Tie::Hash); | |
73 | use strict; | |
74 | ||
75 | sub TIEHASH { | |
76 | my $c = shift; | |
77 | my $s = []; | |
78 | bless $s, $c; | |
79 | while (@_) { | |
80 | $s->STORE(shift, shift); | |
81 | } | |
82 | return $s; | |
83 | } | |
84 | ||
85 | sub FETCH { | |
86 | my($s, $k) = @_; | |
778e8f97 EA |
87 | if (ref $k) { |
88 | if (defined $s->[0]{"$k"}) { | |
89 | $s->[0]{"$k"}[1]; | |
90 | } | |
91 | else { | |
92 | undef; | |
93 | } | |
94 | } | |
95 | else { | |
96 | $s->[1]{$k}; | |
97 | } | |
5f05dabc | 98 | } |
99 | ||
100 | sub STORE { | |
101 | my($s, $k, $v) = @_; | |
102 | if (ref $k) { | |
103 | $s->[0]{"$k"} = [$k, $v]; | |
104 | } | |
105 | else { | |
106 | $s->[1]{$k} = $v; | |
107 | } | |
108 | $v; | |
109 | } | |
110 | ||
111 | sub DELETE { | |
112 | my($s, $k) = @_; | |
113 | (ref $k) ? delete($s->[0]{"$k"}) : delete($s->[1]{$k}); | |
114 | } | |
115 | ||
116 | sub EXISTS { | |
117 | my($s, $k) = @_; | |
118 | (ref $k) ? exists($s->[0]{"$k"}) : exists($s->[1]{$k}); | |
119 | } | |
120 | ||
121 | sub FIRSTKEY { | |
122 | my $s = shift; | |
da41ffc5 GS |
123 | keys %{$s->[0]}; # reset iterator |
124 | keys %{$s->[1]}; # reset iterator | |
5f05dabc | 125 | $s->[2] = 0; |
126 | $s->NEXTKEY; | |
127 | } | |
128 | ||
129 | sub NEXTKEY { | |
130 | my $s = shift; | |
131 | my ($k, $v); | |
132 | if (!$s->[2]) { | |
133 | if (($k, $v) = each %{$s->[0]}) { | |
134 | return $s->[0]{"$k"}[0]; | |
135 | } | |
136 | else { | |
137 | $s->[2] = 1; | |
138 | } | |
139 | } | |
140 | return each %{$s->[1]}; | |
141 | } | |
142 | ||
143 | sub CLEAR { | |
144 | my $s = shift; | |
145 | $s->[2] = 0; | |
146 | %{$s->[0]} = (); | |
147 | %{$s->[1]} = (); | |
148 | } | |
149 | ||
778e8f97 EA |
150 | package Tie::RefHash::Nestable; |
151 | use vars '@ISA'; @ISA = qw(Tie::RefHash); | |
152 | ||
153 | sub STORE { | |
154 | my($s, $k, $v) = @_; | |
155 | if (ref($v) eq 'HASH' and not tied %$v) { | |
156 | my @elems = %$v; | |
157 | tie %$v, ref($s), @elems; | |
158 | } | |
159 | $s->SUPER::STORE($k, $v); | |
160 | } | |
161 | ||
5f05dabc | 162 | 1; |