my $foo;
print_foo();
$foo = "Hello\n";
print_foo();

sub print_foo {print $foo;}

##</code><code>##

my %data = default_data();

sub whatever {
  my $self = shift;
  # ...
}

##</code><code>##

{
  my %private_stuff;
  sub some_func {
    unless (%private_stuff) {
      %private_stuff = qw(some defaults);
    }
    # ...
  }
}