#!/usr/local/bin/perl -w

use strict;

package A;

use vars qw(%DATA);

%DATA=('name' => 'A name',
       'data' => 'A data'
      );

sub new {
  my $class=shift;
  my $self={};

  bless $self, $class;
}

sub init {
  my $self=shift;
  my $class=ref($self);
  $self->initData($class);
  # other initialization here
}

sub initData {
  my ($self, $class, $visited)=@_;
  $visited={} unless $visited;
  # First visit all the superclasses
  no strict 'refs';
  foreach my $c (@{"${class}::ISA"}) {
    $self->initData($c, $visited);
  }
  # Now take my own %DATA hash
  if (!exists($visited->{$class})) {
    $self->copyData(%{"${class}::DATA"});
    $visited->{$class}=1;
  }
}

sub copyData {
  my $self=shift;
  my %data=@_;
  $self->{$_}=$data{$_} foreach keys(%data);
}

####################

package B;

use vars qw(@ISA %DATA);

@ISA=qw(A);

%DATA=('name' => 'B name');

1;