#!/usr/bin/perl

package Foo;
use Alter;
use strict;

sub new {
  my $class   = shift;
  my $hashref = bless {}, $class;
  Alter::alter($hashref, {});
  $hashref;
}

sub attr : lvalue {
  my $self = shift;
  my $attr = shift;
  my $ego = Alter::ego($self);
  if (@_) {
    $ego->{$attr} = shift;
  }
  $ego->{$attr};
}

package main;
use strict;

my $foo = Foo->new();

print "\$foo is a HASH\n" if $foo->isa('HASH');
$foo->{foo} = 'bar';
$foo->attr('foo') = 'quux';

print "\$foo->{foo} = $foo->{foo}\n";
print "attr \$foo('foo') = ", $foo->attr('foo'),"\n";
__END__
$foo is a HASH
$foo->{foo} = bar
attr $foo('foo') = quux