#!/usr/bin/perl
use strict;
use warnings;
use 5.010;

# Closure = Object with 1 method
# Hash + Closures = Object with more than 1 method

sub fibby {
	# some initial state
	my($a,$b) = (0,1);
	# and our methods
	my $object = {
		# a 'method' for giving us the next fibonacci number
		move_forward => sub {
			($a,$b) = ($b,$a+$b);
			$a;
		},
		# and another one for moving backwards
		move_back => sub {
			($a,$b) = ($b-$a,$a);
			$a;
		}
	};
}

my $fibonacci_object = &fibby();
say "First lets move forward.";
foreach my $i (1..10) {
	# the notation for 'method' calls is a little ugly but that's because I'm a perl newbie
	say "F_$i is ", &{$fibonacci_object->{move_forward}}();
}

say "Now lets move back.";
foreach my $i (reverse (1..9)) {
	say "F_$i is ", &{$fibonacci_object->{move_back}}();
}