#!/usr/bin/env perl

use 5.010_001;
use strict;
use warnings;

package My::Base;

use mro;

our %conf;

sub new {
    my ($class) = @_;

    bless {} => $class;
}

sub configure {
    my ($class, $opts) = @_;

    {
        no strict 'refs';
        %{$class . '::conf'} = (%{$class . '::conf'}, %$opts);
    }

    $_->configure($opts) for @{mro::get_isarev($class)};

    return;
}

package My::Trunk;

use parent -norequire, 'My::Base';

our %conf;

package My::Branch_A;

use parent -norequire, 'My::Trunk';

our %conf;

package My::Branch_B;

use parent -norequire, 'My::Trunk';

our %conf;

package main;

# Everything after here is for demo purposes only.

use Data::Dump;

say '*** Normal instantiation';
say 'My::Base object: ', My::Base::->new();
say 'My::Trunk object: ', My::Trunk::->new();
say 'My::Branch_A object: ', My::Branch_A::->new();
say 'My::Branch_B object: ', My::Branch_B::->new();

say "\n*** My::Base::->configure({A => 1});";
My::Base::->configure({A => 1});
_show_configs();

say "\n*** My::Trunk::->configure({B => 2, C => 3});";
My::Trunk::->configure({B => 2, C => 3});
_show_configs();

say "\n*** My::Branch_A::->configure({A => 'me', D => 4});";
My::Branch_A::->configure({A => 'me', D => 4});
_show_configs();

say "\n*** My::Branch_B::->configure({B => 'me', E => 5});";
My::Branch_B::->configure({B => 'me', E => 5});
_show_configs();

sub _show_configs {
    say 'My::Base::conf';
    dd \%My::Base::conf;
    say 'My::Trunk::conf';
    dd \%My::Trunk::conf;
    say 'My::Branch_A::conf';
    dd \%My::Branch_A::conf;
    say 'My::Branch_B::conf';
    dd \%My::Branch_B::conf;
}