$mod =~ s{::}{/}g;
$mod .= '.pm';

##</code><code>##

#!/usr/bin/env perl

use strict;
use warnings;
use Data::Dumper;

my $json = q/{"hello":["world","collegues"]}/;

print Dumper $_
    for map { +{
                module  => $_,
                input   => $json,
                output  => $_->new->decode($json),
        } }
        grep {
            m/^JSON::(?:PP|XS)$/
            && eval "require $_"
        } @ARGV;

##</code><code>##

davido@davido-desktop:~/scripts$ perl mytest.pl JSON::XS JSON::PP Disallowed::Module
$VAR1 = {
          'input' => '{"hello":["world","collegues"]}',
          'output' => {
                        'hello' => [
                                     'world',
                                     'collegues'
                                   ]
                      },
          'module' => 'JSON::XS'
        };
$VAR1 = {
          'input' => '{"hello":["world","collegues"]}',
          'module' => 'JSON::PP',
          'output' => {
                        'hello' => [
                                     'world',
                                     'collegues'
                                   ]
                      }
        };