#!/usr/bin/perl -w
use strict;

sub get_stuff {
  my $ref = shift;

  if (ref $ref) {
    if (ref $ref eq 'SCALAR') {
      $$ref = 'This is a scalar';
    } elsif (ref $ref eq 'ARRAY') {
      @$ref = qw(This is an array);
    } elsif (ref $ref eq 'HASH' ) {
      %$ref = (1 => 'This',
	       2 => 'is',
	       3 => 'a',
	       4 => 'Hash');
    } else {
      die "Invalid reference type passed to get_stuff.\n";
    }
  } else {
    die "Non-reference passed to get_stuff.\n";
  }
}

my ($scalar, @array, %hash);

get_stuff(\$scalar);
get_stuff(\@array);
get_stuff(\%hash);

print "$scalar\n";
$"='|';
print "@array\n";
print map { $hash{$_} . ' ' } sort keys %hash;