protected function getOptionDataByOptionKey() {
    if (!isset($this->option_data_by_name)) {

      $this->option_data_by_name = array();
      foreach ($this->argument_spec_data['options'] as $argument_spec) {
        if (strlen($argument_spec['short'])) { $this->option_data_by_name[$argument_spec['short']] = $argument_spec; }
        if (strlen($argument_spec['long'])) { $this->option_data_by_name[$argument_spec['long']] = $argument_spec; }
      }
    }
    return $this->option_data_by_name;
  }