use strict;
use warnings;
use Data::Dumper;
$Data::Dumper::Terse = 1; # Raw structures, no $VAR1 style names.

# One hash, with a (hash) reference taken to it–
my %stuff = ( somekey => "someval", o => "hai" );
my $stuff_ref = \%stuff; # reference literally *references* original.
print "Same hash, two ways to access: $stuff{o} eq $stuff_ref->{o}\n";

# See the hash right now.
print "Original hash: ", Dumper( $stuff_ref );

my $value = delete $stuff_ref->{o};
print "Hash after deleting key o: ", Dumper( $stuff_ref );
print "Print it directly (uninitialized now): o => ", $stuff_ref->{o}, $/;

# Add a new dimension to the data–
$stuff_ref->{new_key}{sub_key} = "new value";

# Give it a friend, old key/value, new position–
$stuff_ref->{new_key}{o} = $value;

print "Hash after moving stuff around: ", Dumper( $stuff_ref );

$stuff_ref->{as}{deep}{as}{you} = "please";
$stuff_ref->{as}{deep}{as}{array_ref} = [ "one", "two" ];
$stuff_ref->{subroutine} = sub { print "OHAI!\n" };
$stuff_ref->{fancy_data} = [ "one", { two => "is a hash(ref)" }, ["another","array"], "last" ];

print "Perl data structures are *flexible* ", Dumper( $stuff_ref );

print "Excecuting code ref through data...";
$stuff_ref->{subroutine}->();