RE: Deep Copy

[Marcos . Rebelo]

see:

use strict;
use Data::Dumper;

sub simpleClone($){
    my ($toClone) = @_;
    my $Return;
    if (ref($toClone) eq 'HASH'){
        $Return = {};
        while (my ($key, $value) = each(%$toClone)){
            $Return->{$key} = simpleClone($value);
        }
    } elsif (ref($toClone) eq 'ARRAY') {
        $Return = [];
        @$Return = map{simpleClone($_)}(@$toClone);
    } else {
        $Return = $toClone;
    }
    
    return $Return;
}

my $a = {a=>[1,2,3], b=>{a=>4, b=>5}, c=>6};
my $b = simpleClone($a);
print ":::::::::::::::::::::::::::::::::::\n";
print "a: ".Dumper($a);
print "b: ".Dumper($b);

print ":::::::::::::::::::::::::::::::::::\n";
$b->{d} = 2;
print "a: ".Dumper($a);
print "b: ".Dumper($b);

print ":::::::::::::::::::::::::::::::::::\n";
$b->{c} = 2;
print "a: ".Dumper($a);
print "b: ".Dumper($b);
print ":::::::::::::::::::::::::::::::::::\n";





This code is just for HASH and ARRAY and simpler SCALAR, but must be ease to
be extended

Thanks
Marcos Rebelo

-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]
Sent: Tuesday, July 29, 2003 11:29 PM
To: [EMAIL PROTECTED]
Subject: Deep Copy


I am trying to make a deep copy in a complex data structure. I have a hash
that has all of its values as anonymous arrays. I need to copy the entire
hash as a completely separate hash so that I can manipulate the data in the
copy without affecting the original data. Copying the key of the hash is
easy, that is plain data. However copying the value is harder because it is
the anonymous array (so whenever I try to copy the data, it always copies
the reference to the array).

-----------------------------------------
my $hashref;

sub hashref()
{
  return $hashref; 
}

$hashref->{ele1} = ["val1", "val2"];
$hashref->{ele2} = ["val3", "val4"];
$hashref->{ele3} = ["val5", "val6"];

my %newhash = %$hashref;

my @keys = keys(%newhash);
foreach my $arraykey (@keys)
{
    my $ref = $hashref->{$arraykey};
    $newhash{$arraykey} = @$ref;
}
---------------------------------------------------

But then when I do: 

--------------------------------------------------
$newhash{ele1}->[0]="x";
$newhash{ele2}->[0]="y";

print $hashref->{ele1}->[0];
print $hashref->{ele2}->[0];
------------------------------------------------

It changes the values in both the referenced hash and the copied hash. How
do I get a real copy?

TIA

Brian Seel

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