#!/usr/bin/env perl
use utf8;
###############################################################################
# This program demonstrates the Stack ADT
# 
# Copyright © 2021 Richard Lesh.  All rights reserved.
###############################################################################

use Error::Simple;
use Nice::Try;
use Utils;
use strict;
use warnings;

package IntegerStack {
# Internal representation for the stack is a list

	sub new {
		my $class = shift @_;
		my $self = {};
		$self->{'stack'} = [];
		bless $self, $class;
		return $self;
	}

	sub pop {
		my ($self) = @_;
		if (scalar(@{$self->{'stack'}}) == 0) {
			die Error::RuntimeException->new("Can't pop on empty stack!");
		}
		return pop(@{$self->{'stack'}});
	}

	sub push {
		my ($self, $value) = @_;
		push(@{$self->{'stack'}}, $value);
	}

	sub peek {
		my ($self) = @_;
		if (scalar(@{$self->{'stack'}}) == 0) {
			die Error::RuntimeException->new("Can't peek on empty stack!");
		}
		return $self->{'stack'}->[scalar(@{$self->{'stack'}}) - 1];
	}
}

MAIN:
{
	binmode(STDOUT, ":utf8");
	binmode(STDERR, ":utf8");
	binmode(STDIN, ":utf8");
	my $stack = new IntegerStack();
	for (my $x = 1; $x <= 10; ++$x) {
		$stack->push($x);
	}
	try {
		print $stack->peek(), "\n";
		for (my $x = 1; $x <= 11; ++$x) {
			print $stack->pop(), "\n";
		}
	} catch (Error::RuntimeException $ex) {
		print $ex, "\n";
	} catch (Error::Simple $ex) {
		print "Unknown Exception!\n";
	}
}