#!/usr/bin/perl

use strict;
use warnings;

#use Foo::Bar;
#use Bar::Baz;

use Module::Load::Conditional 'can_load';
BEGIN { my $modules = [ map {$_} qw[
IPC::Cmd
Foo::Bar
Bar::Baz
]];

my @install = do { local @_;
  for my $m (@$modules) { push @_, $m
  unless can_load(modules => {$m,undef},
  autoload => 1)} @_
};

@install and do {
  print 'Install required modules ',
  join(' ', @install), ' from CPAN? (y)/n ';
  
  my $in = <STDIN>; chomp $in; $in ||= 'y';
  my $cpanm = IPC::Cmd::can_run('cpanm');

  if (lc $in eq 'y') {
    if ($cpanm) {

      print 'Use 1. cpan or 2. cpanm 1/(2) ';

      my $cpan = do { local $_ = <STDIN>; chomp $_; $_ ||= 2;
      $_ = 2 unless /^1|2$/; $_ };

      if ($cpan == 2) {
        unless (system $cpanm, '-v', @install) {
          system 'perl', $0, @ARGV;
          exit
        }
      }
    }
    unless (system 'cpan', @install) {
      system 'perl', $0, @ARGV;
      exit
    }
  }
  else{
    die "Install required perl modules:\n".
    join ' ', 'cpan',  @install, "\n".
    ($cpanm ? join(' ', 'cpanm', @install) : '')."\n\n".
    "Can't locate ".join(' ',@install).' in @INC '.
    '(@INC contains: '.join(' ', @INC).") \n"
  }
};

Bar::Baz->import('Something')}