$ast = {
         'date' => undef,
         'author' => 'agent',
         'ram' => {
                    'word_size' => 16,
                    'delay' => 2
                  },
         'alu' => {
                    'word_size' => 32,
                    'sels' => [
                                'MUL',
                                'DIV'
                              ],
                    'delay' => 3
                  }
       };
