$VAR1 = {
          'max_childrensubtree' => '7',
          'port' => '1984',
          'user' => 'someuser',
          'password' => 'somepw',
          'max_width' => '20',
          'host' => 'localhost',
          'attrs' => {
                       'subattr2' => 'cat',
                       'topattr1' => 'cat',
                       'subattr2_1' => 'pt',
                       'subattr1' => 'rel'
                     },
          'max_descendants' => '1000'
        };

(
  a => {
    'key1' => 'ok',
    'key2' => 'hello'
  }
)

(
  'key1' => 'ok',
  'key2' => 'hello'
)

#!/usr/bin/perl
use utf8;
use strict;
use warnings;

use Data::Dumper;

my %ini = (
        'params' => {
                      'max_width' => '20',
                      'max_childrensubtree' => '7',
                      'max_descendants' => '1000'
                    },
        'attrs' => {
                     'topattr1' => 'cat',
                     'subattr1' => 'rel',
                     'subattr2' => 'cat',
                     'subattr2_1' => 'pt',
                   },
        'basex' => {
                     'host' => 'localhost',
                     'port' => '1984',
                     'user' => 'someuser',
                     'password' => 'somepw'
                   }
);

&_parse_ini(%ini);

sub _parse_ini {
  my $ref = shift;

  foreach (('params', 'basex')) {
    foreach my $k (keys %{$ref->{$_}}) {
        $ref->{$k} = $ref->{$_}->{$k};
    }
    delete $ref->{$_};
  }

  print Dumper($ref);
}

#!/usr/bin/perl
use utf8;
use strict;
use warnings;

use Data::Dumper;
use Config::IniFiles;

# Load config file
tie my %ini, 'Config::IniFiles', (-file => $ARGV[0]);

&_parse_ini(%ini);

sub _parse_ini {
  my $ref = shift;

  foreach (('params', 'basex')) {
    foreach my $k (keys %{$ref->{$_}}) {
        $ref->{$k} = $ref->{$_}->{$k};
    }
    delete $ref->{$_};
  }

  print Dumper($ref);
}

[params]
max_width = 20
max_childrensubtree = 7
max_descendants = 1000

[attrs]
topattr1 = cat
subattr1 = rel
subattr2 = cat
subattr2_1 = pt

[basex]
host = localhost
port = 1984
user = admin
password = admin