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162 lines
3.1 KiB
162 lines
3.1 KiB
package Tie::RefHash;
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=head1 NAME
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Tie::RefHash - use references as hash keys
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=head1 SYNOPSIS
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require 5.004;
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use Tie::RefHash;
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tie HASHVARIABLE, 'Tie::RefHash', LIST;
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tie HASHVARIABLE, 'Tie::RefHash::Nestable', LIST;
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untie HASHVARIABLE;
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=head1 DESCRIPTION
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This module provides the ability to use references as hash keys if you
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first C<tie> the hash variable to this module. Normally, only the
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keys of the tied hash itself are preserved as references; to use
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references as keys in hashes-of-hashes, use Tie::RefHash::Nestable,
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included as part of Tie::RefHash.
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It is implemented using the standard perl TIEHASH interface. Please
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see the C<tie> entry in perlfunc(1) and perltie(1) for more information.
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The Nestable version works by looking for hash references being stored
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and converting them to tied hashes so that they too can have
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references as keys. This will happen without warning whenever you
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store a reference to one of your own hashes in the tied hash.
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=head1 EXAMPLE
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use Tie::RefHash;
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tie %h, 'Tie::RefHash';
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$a = [];
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$b = {};
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$c = \*main;
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$d = \"gunk";
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$e = sub { 'foo' };
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%h = ($a => 1, $b => 2, $c => 3, $d => 4, $e => 5);
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$a->[0] = 'foo';
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$b->{foo} = 'bar';
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for (keys %h) {
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print ref($_), "\n";
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}
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tie %h, 'Tie::RefHash::Nestable';
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$h{$a}->{$b} = 1;
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for (keys %h, keys %{$h{$a}}) {
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print ref($_), "\n";
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}
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=head1 AUTHOR
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Gurusamy Sarathy [email protected]
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=head1 VERSION
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Version 1.3 8 Apr 2001
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=head1 SEE ALSO
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perl(1), perlfunc(1), perltie(1)
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=cut
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use v5.6.0;
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use Tie::Hash;
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use strict;
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our @ISA = qw(Tie::Hash);
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our $VERSION = '1.3';
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sub TIEHASH {
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my $c = shift;
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my $s = [];
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bless $s, $c;
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while (@_) {
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$s->STORE(shift, shift);
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}
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return $s;
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}
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sub FETCH {
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my($s, $k) = @_;
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if (ref $k) {
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if (defined $s->[0]{"$k"}) {
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$s->[0]{"$k"}[1];
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}
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else {
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undef;
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}
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}
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else {
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$s->[1]{$k};
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}
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}
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sub STORE {
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my($s, $k, $v) = @_;
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if (ref $k) {
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$s->[0]{"$k"} = [$k, $v];
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}
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else {
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$s->[1]{$k} = $v;
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}
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$v;
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}
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sub DELETE {
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my($s, $k) = @_;
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(ref $k) ? delete($s->[0]{"$k"}) : delete($s->[1]{$k});
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}
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sub EXISTS {
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my($s, $k) = @_;
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(ref $k) ? exists($s->[0]{"$k"}) : exists($s->[1]{$k});
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}
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sub FIRSTKEY {
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my $s = shift;
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keys %{$s->[0]}; # reset iterator
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keys %{$s->[1]}; # reset iterator
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$s->[2] = 0;
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$s->NEXTKEY;
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}
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sub NEXTKEY {
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my $s = shift;
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my ($k, $v);
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if (!$s->[2]) {
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if (($k, $v) = each %{$s->[0]}) {
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return $s->[0]{"$k"}[0];
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}
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else {
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$s->[2] = 1;
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}
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}
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return each %{$s->[1]};
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}
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sub CLEAR {
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my $s = shift;
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$s->[2] = 0;
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%{$s->[0]} = ();
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%{$s->[1]} = ();
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}
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package Tie::RefHash::Nestable;
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our @ISA = qw(Tie::RefHash);
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sub STORE {
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my($s, $k, $v) = @_;
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if (ref($v) eq 'HASH' and not tied %$v) {
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my @elems = %$v;
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tie %$v, ref($s), @elems;
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}
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$s->SUPER::STORE($k, $v);
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}
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1;
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