my $default = 0;
my $input_number = $ARGV[0];

my $number = defined $input_number ? $input_number : $default;

##</code><code>##

my $number = $input_number // $default;

##</code><code>##

my $default_theme = get_default_theme();
my $global_config = read_config('/path/to/config_file');
my $theme_config = read_config($global_config->{theme_file});
my $current_mode = get_current_mode();

my $theme = defined $global_config->{modes}{$current_mode}{theme} ?
                    $global_config->{modes}{$current_mode}{theme} :

            defined $theme_config->{current_theme}                ?
                    $theme_config->{current_theme}                :

            defined $default_theme                                ?
                    $default_theme                                :

                    'none';

##</code><code>##

my $theme = $global_config->{modes}{$current_mode}{theme} //
            $theme_config->{current_theme} //
            $default_theme //
            'none';

##</code><code>##

my $theme = (
              (
                $global_config->{modes}{$current_mode}{theme}
                //
                $theme_config->{current_theme}
              )
               //
               $default_theme
            )
            //
            'none';