use strict;
use warnings;
no warnings qw/once/;

package Alter;

my %data;

sub ego {
    return( $data{scalar caller(0)} ||= {} );
}

package Plugin;

sub foo {
    $_[0]->ego()->{name} = $_[1] if @_ >  1;
    return $_[0]->ego()->{name};
}

package MyClass;

*ego = \&Alter::ego;
*foo = \&Plugin::foo;

sub bar {
    $_[0]->ego()->{name} = $_[1] if @_ >  1;
    return $_[0]->ego()->{name};
}

package main;

my $obj = bless( \my $scalar, "MyClass" );

$obj->bar( "Larry" );
$obj->foo( "Damian" );

for my $m ( qw/bar foo/ ) {
    print "$m: ", $obj->$m, "\n";
}


##</code><code>##

bar: Larry
foo: Damian