use Shell qw(echo cat ps cp);

##</code><code>##

package Class::FlyweightWrapper;
$VERSION = 0.01;
use strict;
use Carp;

my $BASE_PACKAGE = <<'EOT';

# line 1 "'Flyweight wrapper PUBLIC for PRIVATE'"
  package PUBLIC;

  my %object = qw(PUBLIC PRIVATE);
  
  sub DESTROY {
    delete $object{$_[0]};
  }
  
  sub AUTOLOAD {
    my $meth = $PUBLIC::AUTOLOAD;
    $meth =~ s/.*:://;
    my $self = $object{shift(@_)};
    return $self->$meth(@_);
  }
  
  sub can {
	my $self = $object{shift(@_)};
	my ($method_name) = @_;
	return $self->can($method_name);
  }
  
  # Make sure things cleanup properly
  END {
    %object = ();
  }
EOT

my $BASIC_CONSTRUCTOR = <<'EOT';
  sub CONSTRUCTOR {
    my $self = bless \ my $scalar, "PUBLIC";
    my $class = shift;
    $object{$self} = $object{$class}->CONSTRUCTOR(@_);
    $self;
  }
EOT


sub import {
  shift; # Not interested in my package
  my $public = shift
    || croak("Usage: use Class::FlyweightWrapper 'Public::Package';");
  my $private = caller();
  my @constructors = @_ ? @_ : 'new';

  my $template = $BASE_PACKAGE;
  $template =~ s/PUBLIC/$public/g;
  $template =~ s/PRIVATE/$private/g;

  foreach (@constructors) {
    my $piece = $BASIC_CONSTRUCTOR;
    $piece =~ s/CONSTRUCTOR/$_/g;
    $piece =~ s/PUBLIC/$public/g;
    $piece =~ s/PRIVATE/$private/g;
    $template .= $piece;
  }
  
  eval $template;
  if ($@) {
    confess("Template\n$template\ngave error $@");
  }
}

1;

##</code><code>##

#!/usr/bin/perl

package Test::Private;

use Class::FlyweightWrapper "Test::Public";

sub new {
	return bless {}, ref($_[0]) || $_[0];
}

sub helloWorld {
	print "Hello World!\n";
}

package DerivedTest;

@DerivedTest::ISA = qw(Test::Public);

package main;

my $test = Test::Public->new();
$test->helloWorld();

print (($test->can("helloWorld")) ? "we can\n" : "we can't\n");

my $test2 = DerivedTest->new(); # <<< dies here
$test2->helloWorld();

print (($test2->can("helloWorld")) ? "we can\n" : "we can't\n");

1;

##</code><code>##

Hello World!
we can
Can't call method "new" on an undefined value at 'Flyweight wrapper Test::Public for Test::Private' line 24.