The use of

  $class = ref($class) || $class;

is unneeded 90% of the time, and insufficient for 90% of the rest of the time.

If you want a clone method, use a clone or copy method on an instance. If you want another object of the same class as the first object, use

  my $two = ref($one)->new(@parms);

Which reduces our canonical simple constructor to:

  sub new {
    my $class = shift;
    my $self = { @_ };
    bless $self, $class;

Nice and simple.