sub gen_closure {
    my ($a, $b, $c) = @_;
    return sub {
        if ($some_trigger) {
            # Calculate new $a, $b, $c based on e.g. the
            # new @_ and the old $a, $b and $c. 
            return gen_closure($new_a, $new_b, $new_c);
        }
        # Do the normal closure action on $a, $b and $c here
     }
}