#!/usr/bin/env perl

use 5.010;
use strict;
use warnings;

package A;

sub new { bless {} => $_[0] }

sub seen_once { 1 }
sub seen_twice { 1 }
sub seen_thrice { 1 }

package A::B;

use parent -norequire => 'A';

sub seen_twice { 1 }
sub seen_thrice { 1 }

package A::B::C;

use parent -norequire => 'A::B';

sub seen_thrice { 1 }

package main;

use mro;

my $instantiation_class = 'A::B::C';
my @methods = qw{seen_once seen_twice seen_thrice seen_never};
my $isa = mro::get_linear_isa($instantiation_class);
my %found;

say "Instantiation class: $instantiation_class";

my $obj = $instantiation_class->new;
say 'Objects blessed into class: ', ref $obj;

say 'Method Resolution:';

METHOD:
for my $method (@methods) {
    next METHOD if exists $found{$method};

    CLASS:
    for my $class (@$isa) {
        {
            no strict 'refs';
            next CLASS unless exists ${$class . '::'}{$method};
        }
        ++$found{$method};
        say "$method()\tfound first in $class";
        last CLASS;
    }

    unless (exists $found{$method}) {
        say "$method()\tNOT found in OO hierarchy!";
    }
}