$hash{ 'key1' }{ 'key2' }

##</code><code>##

     $hash{ 'key1' } = 'foo';
     $hash{ 'key1' }{ 'key2' } = 'bar'; # (2)

     # (2) means find %(current pkg)::foo and do
     $(current pkg)::foo{ 'key2' } = 'bar';

##</code><code>##

     my %hash;
     $hash{ 'key1' } = {}; ## ref to hash

     $hash{ 'key1' }->{ 'key2' } = 'foo';

     ## above equivalent to
     my %hash = (
           key1 => {
                  key2 => 'foo'
           }
     );

##</code><code>##

       $hash{ 'key1' } = 'foo';
       $hash{ 'key1', 'key2' } = 'bar';

##</code><code>##


       my %hash = (
             food => {
                   name => 'Apple',
                   color => 'Red'
             }
       );

       my $food = $hash{ 'food' };
       print "$food->{ 'color' } $food->{ 'name' }\n";