#!/usr/bin/perl -w

use strict;
use Data::Dumper;

my @array = (
[1],
[],
{1 => 2, 2 =>{}}
);

clean(\@array);

print Dumper(\@array);

sub clean
{
      my $ref = shift;

      my $ref_name = ref($ref);

      if ($ref_name eq "SCALAR") {
            return 1;
      }
      elsif ($ref_name eq "ARRAY") {

            my $n = scalar(@$ref);
            for(my $i = 0; $i < $n; $i++) {
                  my $result = clean($ref->[$i]);

                  if ($result == 0) {
                        delete($ref->[$i]);
                  }
            }

            $n = scalar(@$ref);
            if ($n == 0) {
                  return 0;
            }

            return 1;
      }
      elsif ($ref_name eq "HASH") {
            while(my ($key, $value) = each( %$ref))
            {
                  my $result = clean($value);
                  if ($result == 0) {
                        delete($ref->{$key});
                  }
            }

            my $n = scalar(keys %$ref);
            if ($n == 0) {
                  return 0;
            }
            return 1;
      }
      elsif ($ref_name eq "REF") {
            die "incorrect reference submitted to function clean\n";
      }
      else {
            clean(\$ref_name);
      }

}

##</code><code>##

$VAR1 = [
          [
            1
          ],
          undef,
          {
            '1' => 2
          }
        ];