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

package Scalar;
use Carp;
use overload 
    q(bool) => sub { carp q(bool); return !!${$_[0]} },
    q("")   => sub { carp q(""); return ${$_[0]} . "" },
    q(0+)   => sub { carp q(0+); return ${$_[0]} + 0  },
    fallback => 1;

sub new { 
    my $class = shift;
    my $val   = shift;
    bless \$val, $class;
}
1;

package main;
local $\ = "\n";

my $t = Scalar->new(1);
my $f = Scalar->new(0);
print 'true'  if $t;
print 'false' if $f;
print 'and' if $f && $t;
print 'or'  if $f || $t;
print $f + $t;
print $f . $t;