It's worth noting that Data::Dumper (core) and Data::Dump (my favorite) and many other, similar modules are designed to produce text that is compilable code. So compiling and running the exact OPed Data::Dumper output (with strict disabled!):

$VAR1 = {
           'key' => {
                      'innerkey2' => [
                                       'here'
                                     ],
                      'innerkey3' => [
                                       'there'
                                     ],
                      'innerkey1' => [
                                       'hello',
                                       'world'
                                     ]
                    }
         };

print Dumper $VAR1;
[download]

will produce output that is an exact image (replica?) of the structure defined (and that is, in turn, compilable). If you like using strict (a wise choice IMHO), just pre-define the variable with our or, usually better because lexical, my. If you don't like the name, call it something else.

use warnings;
use strict;

use Data::Dump qw(dd);

my $something_else = {
    ...,
    };
dd $something_else;
[download]

Update: For some reason, I can't get either  [mod://Data::Dump] or  [cpan://Data::Dump] to link to the module, but I can see it on CPAN. You'll just have to fend for yourselves.     Later: [mod://Data::Dump] works now. And there was great rejoicing...