retaining original class hierarchy

[Dirk Koopman]

I have a factory class called 'Foo'. It has several subclasses like:
'Foo::TypeA', 'Foo::TypeB' and so on. Each of these subclasses has a
different version of 'method'.

There a stash of objects of these different subclassed type such that a
function Foo::get('main') will return an object of, say, 'Foo::TypeB' -
BUT - you don't know what that object's class will be.

I now want to have something functionally like this: 

package Foo;

our %stash;

sub new
{
    my $pkg = shift;
    my $class = ref $pkg || $pkg;
    my $obj = _get(shift);   # returns a Foo::TypeB
    my $objclass = ref $obj;
    no strict;
    our @{$class}::ISA = $objclass;
    return bless $obj, $class;
}

sub _get
{
   return $stash{shift};
}

and I want to then have something like:-

package Bar;

use base 'Foo';

my $obj = Foo::new('main');

and have the inheritance work so that it looks at 'Foo::TypeB' (or
whatever Foo::new has set @ISA to for that object). In other words
return, dynamically, objects with their own 'private' @ISA setting.

I don't want to know which subclass of Foo that am dealing with in the
program code itself (at least at this point) because it may well change.

Dirk