There's at least a potential hazard in this approach: what if your parent constructor does parameter checking, and is more restrictive than your subclass? Then the above would be dangerous -- you'd lose the values in %params -- and you'd want to do something like:

  my ($class, $whatever) = @_;
  my %params = (); # new params to use instead of parent's params
  my $this = new base_class; # create a new parent, and 
                             # let it set its own defaults
  # clobber the base_class' defaults:
  while (my ($k,$v) = each %params) {
     $this->{$k} = $v;
  }
  bless($this, $class); # re-bless into the current package
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Ugly and hypothetical, but something to be aware of.

On second thought, better still: always make any parameter checking in the constructors throw a fatal error. Note such errors in development and change the parent's constructor to play nice.

-- Frag.
--
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