Heres an annoying little problem with polymorphism. I have 2 classes, call them parent & child, and the constructors take an initialization param whose accessor / mutator is overridden, but the parent initializer always gets called, because in the parent constructor, the object instance is still a parent, not a child.

package parent;

sub new {
   my $class = shift;
   my ($setup_data) = @_;

   my $self = {};
   bless $self, $class;

   $self->_SetupData($setup_data);
   return $self;
}

package child;
use base qw(parent);

sub new {
   my $class = shift;
   my ($setup_data) = @_;

   my $self = $class->SUPER::new($setup_data);

   return $self;
}
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So i understand why child::_SetupData() isnt called from parent::new(), but im looking for a clean way to fix this problem, without taking the initialization out of the constructors, and into a setup method that must be explicitly called.