# example structure
my $struct = {
    fruit   => [qw( apple pear )],
    type    => [qw( organic farmed )],
    period  => {
      20050824 => {
        to  => 'new york',
        to  => 'london',
      },
      20050825 => {
        to  => 'auckland',
      },
    }
  };

##</code><code>##

# expanded into:
my $expanded => [
    { fruit => 'apple', type => 'farmed',   period => 20050824, to => 'london'    },
    { fruit => 'apple', type => 'farmed',   period => 20050824, to => 'new york'  },
    { fruit => 'apple', type => 'farmed',   period => 20050825, to => 'auckland'  },
    { fruit => 'apple', type => 'organic',  period => 20050824, to => 'london'    },
    { fruit => 'apple', type => 'organic',  period => 20050824, to => 'new york'  },
    { fruit => 'apple', type => 'organic',  period => 20050825, to => 'auckland'  },
    { fruit => 'pear',  type => 'farmed',   period => 20050824, to => 'london'    },
    { fruit => 'pear',  type => 'farmed',   period => 20050824, to => 'new york'  },
    { fruit => 'pear',  type => 'farmed',   period => 20050825, to => 'auckland'  },
    { fruit => 'pear',  type => 'organic',  period => 20050824, to => 'london'    },
    { fruit => 'pear',  type => 'organic',  period => 20050824, to => 'new york'  },
    { fruit => 'pear',  type => 'organic',  period => 20050825, to => 'auckland'  },
  ];