use warnings;
use strict;
use feature 'state';

package Library;
sub new { bless {}, shift }
sub logger { # Just an example;
	# could be class or instance method / property,
	# could hand out different logger objects.
	state $logger = Library::Logger->new;
	return $logger;
}

package Library::Logger;
sub new { bless {}, shift }
sub log { shift; print "[".gmtime." UTC] @_\n" }

package Library::Foo;
sub new { bless {}, shift }
sub foo { Library->logger->log("access via class method works") }

package Library::Bar;
use parent -norequire, 'Library';
sub bar { shift->logger->log("inheritance works") }

package Library::Quz;
sub new { my $class = shift; bless {@_}, $class }
sub library { shift->{library} }
sub quz { shift->library->logger->log("access via property works") }

package main;
Library::Foo->new->foo;
Library::Bar->new->bar;
my $lib = Library->new;
$lib->logger->log("access via instance method works");
Library::Quz->new(library=>$lib)->quz;