$VAR1  = {
  'classes' => [
    {
      'classid' => 'xmi.2',
      'classdescription' => undef,
      'methods' => [
        {
          'methoddescription' => '',
          'methodid' => 'xmi.77',
        }
      ],
      'attributes' => [
        {
          'attributedescription' => '',
          'attributeid' => 'xmi.75',
        }
      ],
    },
    {
      'classid' => 'xmi.3',
      'classdescription' => '',
      'methods' => [
        {
          'methoddescription' => '',
          'methodid' => 'xmi.82',
        }
      ],
      'attributes' => [],
    }
  ]
};

##</code><code>##

$descriptions = [
  {
    'id' => 'xmi.2',
    'description' => undef,
  },
  {
    'id' => 'xmi.77',
    'description' => '',
  },
  {
    'id' => 'xmi.75',
    'description' => '',
  },
  {
    'id' => 'xmi.3',
    'description' => ''
  },
  {
    'id' => 'xmi.82',
    'description' => '',
  }
];

##</code><code>##

FOREACH class
  PUT classid, classdescription INTO descriptions
  FOREACH method
    PUT methodid, methoddescription INTO descriptions
  END FOREACH
  FOREACH attribute
    PUT attributeid, attributedescription INTO descriptions
  END FOREACH
END FOREACH