I had to use a complex data structure in a program at work involving hashrefs within arrays within a hash and copying it was a pig because the copied variable contained references to data stored withing the original variable. This led to problems with data corruption and so on. So I came up with deepcopy......
See the difference below. In the first pair %bar contains a pointer to the data contained within %foo but deepcopy seperated the variables.
%foo = (
'x' => [
{
'a' => 1,
'b' => 2
},
100
]
);
%bar = (
'x' => $foo{'x'}
);
%bim = (
'x' => [
{
'a' => 1,
'b' => 2
},
100
]
);
%bom = (
'x' => [
{
'a' => 1,
'b' => 2
},
100
]
);
use Data::Dumper;
use Storable qw(freeze thaw);
# Set up some complex variables, a hash within an array within a hash
my $x = {
a => 1,
b => 2,
};
my %foo = (
x => [$x, 100],
);
# Copy it...
my %bar = %foo;
# Then deepcopy it...
my($bim, $bom) = deepcopy(\%foo, \%bar);
# Then lets have a look inside each variable... ;)
my $dump = Data::Dumper->new([\%foo, \%bar, $bim, $bom], [qw(*foo *bar
+ *bim *bom)]);
print $dump->Dump;
# The sub itself
sub deepcopy {
my @return;
# This sub will take any number of references to a variable and
# parse them all. The result is put into @result and returned as
# an array
while(@_) { push @return, thaw freeze shift; }
return @return;
}
