if ($act eq 'open_file'){ 
    #stuff;
}
elsif ( $act eq 'open_stuff') {
    # stuff; 
} 
elsif ( $act eq 'speak' ) { 
    # stuff;
}
##</code><code>##

package My::Actions;
use Carp;

sub factory {
  my ($class, $action) = @_;
  my %actions = (
    open_file  => 'My::Actions::OpenFile',
    open_stuff => 'My::Actions::OpenStuff',
    speak      => 'My::Actions::Speak'
  );
  croak "Unknown action ($action)" unless exists $actions{$action};
  my $class = $actions{$action};
  return $class->new;  
}

sub do_stuff {
  my $class = shift;
  croak "Class ($class) did not implement do_stuff()";
}

##</code><code>##

use My::Actions;
my $object = My::Actions->factory($act);
$object->do_stuff;