my $instance1 = MyModule::new('1.0');
print $instance1->version();
#prints '1.0';
my $instance2 = MyModule::new('2.0');
print $instance2->version();
#prints '2.0';

##</code><code>##

package MyModule;
our $VERSION = '2.0';
our $vers = {'1.0'=>{__PACKAGE__.'::version'=>\&version_1_0},
             '2.0'=>{__PACKAGE__.'::version'=>\&version_2_0}};

##</code><code>##

sub new {
  my $class = __PACKAGE__;
  my $version = shift || $VERSION;
  return bless({methods=>$$vers{$version}},$class);
}

##</code><code>##

sub AUTOLOAD {
  my $self = $_[0];
  return &{$$self{methods}{$AUTOLOAD}}(@_);
}