1 package toy_module;
  2 
  3 sub new {
  4         my ($class, $args) = @_;
  5         my $self = {
  6                 simple_hash => $args->{simple_hash},
  7                 simple_test_scalar => $args->{simple_test_scalar},
  8         };
  9         print "********** INSIDE SUBROUTINE NEW **********\n";
 10         print "simple scalar: ".$self->{simple_test_scalar}."\n";
 11         print "$_\n" for keys %$self->{simple_hash};
 12         return bless $self, $class;
 13 }
 14 
 15 sub show_simple_hash {
 16         my $self = shift;
 17         print "********** INSIDE SUBROUTINE SHOW_SIMPLE_HASH **********\n";
 18         print "simple scalar: ".$self->{simple_test_scalar}."\n";
 19         print "$_\n" for keys %$self->{simple_hash};
 20 }
 21 
 22 1;

##</code><code>##

  1 use strict;
  2 use warnings;
  3 use lib '~/working/toys';
  4 use toy_module;
  5 
  6 my %little_test_hash = (
  7         COL_1 => 0,
  8         COL_2 => 1,
  9         COL_3 => 2,
 10         COL_4 => 3,
 11         COL_5 => 4,
 12 );
 13 my $little_test_hash_ref = %little_test_hash;
 14 
 15 my $test_object = toy_module->new({simple_hash=>$little_test_hash_ref, simple_test_scalar=>5});
 16 my $next_test = $test_object->show_simple_hash;

##</code><code>##

MacBook-Pro:toys mcrepeau$ perl test_toy_module.pl 
Using a hash as a reference is deprecated at toy_module.pm line 11.
Using a hash as a reference is deprecated at toy_module.pm line 19.
********** INSIDE SUBROUTINE NEW **********
simple scalar: 5
Type of argument to keys on reference must be unblessed hashref or arrayref at toy_module.pm line 11.